The first point you argue against my post is actually quite offensive. Its like saying "oh well, some people assume black people are criminals and we can't do anything about it, because assumptions happen." We have to fight systematic oppression, which includes the idea of heteronormativity - the idea that people are usually simply straight and its fine to assume so is extremely problematic, and its worse to say that its ok to let it slip because some people are just jerks.
I think I phrased it wrong, being offensive definitely wasn’t my intention! And I understand what you’re saying, the idea that someone is automatically born straight isn’t accurate by any means. In an ideal world (that we DO need to fight to achieve), heterosexual wouldn’t just be the default.
But… I still stand by what I said. People make assumptions about sexuality’s, really, as a way to find a partner. It’s biologically implanted in our brains. I think you’re confusing heteronormative thinking for something a lot worse than what it is. While heterosexuality isn’t the only orientation you can be, it is definitely the most common one. Which isn’t a bad thing, unless it’s made to be! People have built up sexualities to be a deciding factor in human beings. And shaming people for being heterosexual/looking at things from a heterosexual POV is also discriminatory (which is what most het shippers do).
Assuming that someone is straight isn’t a bad thing, just like assuming someone is gay/other isn’t necessarily a bad thing (it is only different, in my opinion, because the basis on which people make the assumption that someone is gay is usually incredibly biased generalizations on what it is to be gay). It’s a bad thing when people use it to imply anything but straight is wrong, yes. But a lot of the time, the “double standards” of het shippers are seen as homophobic or that they’re attacking those who are not straight. And only because you mentioned them by name and posted in the Elounor tag, I’ll mention this. Louis is (at least publically) in a heterosexual relationship. It’s very possible that he’s bisexual and only in a relationship with Eleanor to appease that aspect of him, but it can be taken that Louis is interested in women. And until he elaborates further on his sexuality, it can not be said with certainty that he isn’t straight. (But I hate speculating on their sexualities. I don’t know them. It’s none of my business.)
Again, I understand what you’re saying. But I don’t think we need to fight towards reaching a point where people won’t assume the sexuality’s of others; we need to find a way for the sexuality’s of others to not matter or be a reflection of character.