I saw someone asking anyone who think that Tavvy is a rage player to give their answer that doesn't revolve Gamzee in some way (I'm paraphrasing here I don't remember exactly how they ask it)
So I'm going to write it here because I like to write it here.
So warning I haven't reread/listen to homestuck yet in completely so Iay get some info wrong, I'm also going to avoid touching the epilogues as I still haven't gone that far into listening to them to get the full picture so be warned.
My reason for still being firmly on the rage player Tavvy is because rage in homestuck is not something express out ward.
As an example both Makaras (and listen is not cheating if you need to understand other rage players) especially Gamzee it may seem like the dude could freak out and murder anyone in any minute like he did on the meteor, but we have to remember all of this happened after Gamzee was out of sopor and Dave triggered his insanity, and even with the process to get there was slower because his stuck of sopor was running out. So I'm saying his hatred it may have been instantaneous for us but to the characters was really low-key and unnoticed until he killed both Equius and Nepeta and Terezi took noticed.
We also need to look at Gamzee in the later part, from when we see him with Jane to helping Caliborn reach his godhood his rage is really sideline and more put to side by maybe Gamzee himself willing to help destabilise the session like how rage player are describing to do it (you can argue that he wasn't a willing participant about Gamzee because he was possessed by lil Cal, but even then we complete things because we don't know how much control truly lil Cal has over others)
In short from Gamzee as a rage player I see while he initially was angered by Dave video his role in the story as that player continues to be on the side and discrete to others.
Same thing can be apply to Kurloz, we don't see him much of him as a rage player but we he is willing to manipulate things behind the scenes, even helping Gamzee in his quest.
Which makes me conclude that to be a rage player your anger needs to be put somewhere, to be discreet and your burst to be a braking point.
And to quote from the hiveswap aspect description about a rage player "They possess great contempt for lies or false ideas, including the stability that false ideas can impart. To them, the true is far more important than the good; they would tear down a system just to destabilize it if, by their reckoning, it is built on faulty premises."
That the stability of the false ideas, the true (which I'm guessing their own version of the truth) is more important, the way Gamzee freaked out because his religion was mocked in his opinion.
Now where does Tavvy fit in all of this? He fits in all of this thanks to his upbringing, the abusive household he grow up in is the perfect breeding ground to keep any emotions to not leak out which could lead to horrible outback similar to what Gamzee had, while Tavvy doesn't seem like he is delusional in the image his mother try to put he is part of that false idea of their perfect family I feel like an out burst of Jane reality and Tavvy really will happen that will closely align to what a rage player will, (plus Tavvy looks like the perfect example of the quite kid holding the most rage to me).
Now I don't really want to throw around any theorys that could as well be just an au if they don't happen but the possibility of Tavvy shattering Janes lies by him because a troll. And what I mean by that is here on tumblr is a blog that I don't remember the name of but from them I heard this concept of Tavvy or more so a sprite Tavvy prototyping himself with Gamzee for any reason and being revived as a troll. With may not make sense but the themes this route can give him. Especially with Jane is that he will be every she HATES. Not only aligning with the people who "hurt" him but also becoming one of those things, but the worst of it all is she could tell him that everything will be alright they could work things around, hide some fetures, maybe some surgery they can fix it, they can hide it so he can live in the nightmare SHE created. Which could be the braking point for Tavvy to let his rage take over him, because how dare she try to console me after everything she did to discriminate troll and now she wants to do a 180 with me and still persecuting the species, do you actually love me or is this the last ditch of an attempt to keep up your perfect reality, DO YOU SEE THE ACTUAL ME OR ARE YOU SEEING THAT CLOWN IN ME?!!?
That leeds to Tavvyy eyes going orange and disfiguring Candy Jane and killing her in the end.
That's why I believe Tavvyy is rage, funnily my theory is saying any rage players need to be quiet until they can't, which is why I don't believe in Rage Yiffy, you immediately saw an angry girl at a funeral and in that moment she is a rage player/jk