Hmmm. I'm on the fence about this, there's parts that I agree with, parts that I empathize with, and parts that I straight up don't agree with -- but the nature of my disagreement is (hopefully) a reassuring and encouraging kind.
For the original post, about monetizing your hobbies means you are now agreeing to be yelled at -- hard disagree. You are opening yourself up to criticism, absolutely! But I think we should be VERY careful of equating "criticism" to "being yelled at", since there are types of criticism that are indeed appropriate (and which you should reasonably be prepared for) and types that definitely aren't and which border on (or firmly cross the line into) abuse. No one agrees to being abused, even when money is involved.
If I publish a novel, I am indeed agreeing to let people write scathing reviews on the appropriate public venues such as Goodreads, social media, newspaper book columns, and blogs -- my work has a right to exist, and other people have a right to not like it and to talk about not liking it. But I am NOT agreeing to be stalked, doxxed, or the target of a mass harassment/defamation campaign. I am NOT agreeing to let people flood my email inbox or social media DMs with death threats, suicide baiting, or personally-directed mockery. I can and will block them, and it is not petulant or unprofessional of me to do so.
If I make and sell something on Etsy, I am agreeing to communicate with dissatisfied customers, to try to identify the problem, and to fix it if I can -- and, if the problem isn't fixable and the item is still in good condition, I am prepared to accept a return. I'm NOT agreeing to change my whole art style to satisfy an individual customer (ie: "fixing" a piece of intentionally rustic hand embroidery by tearing it out and replacing it with machine-embroidered preset clipart, or re-making a scarf with knitting instead of crochet), and I am NOT agreeing to be stalked/doxxed/harassed/etc. It is not petulant or unprofessional of me to cancel future orders from a customer if I know from past interactions that this person isn't worth the headache.
Monetizing your hobby does have a lot of downsides, but one of the upsides is that you're now the owner of your shop (whether it's physical or digital). You get the responsibility, yes, but you also get the right to politely but firmly ask someone to leave if they're behaving inappropriately. Here's another example that might make more sense: If I owned a cocktail bar, then I'm agreeing to make people the drink they asked for, to bring it over to them in a reasonable amount of time, to avoid allergens if they notify me that there's something I should be careful of, to charge them the price that's listed on the menu plus any applicable local taxes, and to let them write their Yelp reviews. I'm NOT agreeing to let a rowdy drunk start brawls, verbally abuse other customers, assault me or my staff, or act destructively towards my property. If they cross that line, they deserve to be shown to the door and banned from coming back. It's not petulant or unprofessional for me to do that.
So yeah, the exchange of a few dollars DOES open up a social contract between the vendor and the customer, and the vendor should expect and be prepared for some degree of criticism, both reasonable ("When I got this purse, I saw that there's a big hole on the bottom seam where the stitches didn't go through both sides of the material. Can you replace or repair this?") and unreasonable ("Instagram, this is not a good book and nobody should read it!!! it is full of bigotry that never gets addressed. btw i DNFed it on page 5").
But the exchange of the few dollars does NOT mean that you are expected or required to take it lying down like a minimum wage customer service employee during Black Friday. What to do in each circumstance will vary, but the guiding rules are the same as they are for pretty much every other kind of conflict: Behave with honor, know what your principles are, and hold firm to them.
Once, I got someone on Goodreads who left a 2 star review of one of my books and wrote (i quote the review in its entirety): "Meh." I genuinely laughed IRL and said nothing to them. This was correct in the circumstances.
Another time, someone emailed me directly with a LONG wall of text to tell me that they didn't like the use of neopronouns in A Taste of Gold and Iron, that it ruined their experience of the book, and that I shouldn't ever use neopronouns again. I wrote back and told them that they were being rude, inappropriate, and transphobic, and I courteously suggested that they may wish to avoid reading my future books because I will absolutely be using neopronouns again. This was also correct in the circumstances.
In conclusion... I truly sympathize with the fear of criticism. It can feel incredibly daunting to face the prospect of an audience. Even to this day it does make me a bit sad when not Absolutely Everyone In The Whole Wide World loves my work -- but the good news is that over time, you become aware that this deeply-programmed human desire becomes a little silly in any situation outside of "we are a small group of hunter-gatherers killing mammoths with spears, and getting along with my friends is genuinely a crucial survival mechanism."
You ARE allowed to defend yourself when it's appropriate, honorable, and in alignment with your principles.
You ARE allowed to set boundaries (ie: you're not required to read the reviews of your book, and many people actively avoid doing so).
You do NOT have to make yourself available to all criticism at all times (ie: you are not required to respond to that dissatisfied Etsy customer at 1am, you can wait until business hours tomorrow morning -- this is even advisable to do).
You absolutely do NOT have to accept all criticism, because some people are idiots, and some non-idiots still manage to be astonishingly wrong.