CW: Mention of abuse, hateful femicide, incest

This entire thread is very interesting to me (aromantic/quoiromantic) because, while I won't deny any of the problems you're listing, the overall vibe I always got from Homestuck was that it was an aromantic or almost aromantic story.

Almost every romance we see in Homestuck 1 is playful rather than passionate, generally complicated, stressful and short-lived.

It may be a staple of romantic comedies that, if sufficiently dramatic, they end up looking like ANTI-romance advertising... It may be this problem in effect... But what I get from this story is that romance, particularly classical "over-intense" and often carnal romance, is the path to alienation, destruction and self-destruction.

In Act 4, the human kids starting to flirt with the trolls is a theme introduced explicitly in the conversations by Karkat, who sees it very negatively and tells them to stop (which, hilariously, reinforces the June/Vriska and Terezi/Dave flirting). June is lead to her "death" by Vriska, and learns the troll girl is responsible for the creation of their mortal enemy. Things don't end up much better for Dave.

The troll team cooperation is mostly a mess because of their constant romance sitcom, directly criticized by Spades Slick's gaze ("Goddamn kids always smooching each other"), and on the meteor, two of the main triggers for the Murderstuck arc ARE tied to romance: Eridan's unrequited incel fantasies come to the point of explosion, to the point where he challenges Sollux (who, himself, engages with Eridan because of a kind of pride as Feferi's suitor) then kill the girl he supposedly "loved", while Tavros and Vriska's unrelated almost-kismesissitude culminate in another duel with a lethal conclusion. You may even say that the final conversation between Vriska and Terezi, and the fact Terezi fails to murder Vriska in a prediction, and decides to kill her in the first timeline, are all rooted in their romantic tension.

Act 6 is famous for how much potentially non-platonic romance collapses into drama, and how particularly unhealthy these kinds of relationships can be. We see Dirk/Jake as this unhealthy association doomed from the start, with a lovable goofball/pileup of weaponized incompetence Jake paired with a very self-hating and manipulative Dirk, while Roxy and Jane are devoured by loneliness and complex feelings of attraction. Meanwhile, the spades rapprochement between Terezi and Gamzee (with Gamzee positioned in an obvious predatory role) is shown as the most toxic and nightmarish one, it's abuse 101. And Jade and Davesprite live and break their entire story offscreen, a story that doesn't seem to leave either of them the slightest bit relaxed or satisfied.

There's also the incestuous or pseudo-incestuous angle. Early on, the Harlbert and Strilonde siblings, ignoring their genetic ties, are interested in each other, but these attractions are revealed to be impossible, while it is indicated in the book commentary that Doomed Dave and Doomed Rose had a romantic relationship in their doomed "Calsprite" timeline. Memories that ended up in Rose, then in Jasprose, while Doomed Dave became Davesprite, then Davepeta. In one of the most uncomfortable conversations of the entire webcomic, Davepeta openly proposes Jasprose to date again. In parallel, mixed troll reproductive fluids are called "incestuous slurry", while Cherubs are said to "seek a partner who looks like their defeated opposite gender personality" (meaning that Caliborn, had he normally natured rather than stunted his growth, would have roamed the cosmos in search of a pseudo-Calliope as a romantic partner, basically looking for his sister to bone).

So what does Homestuck tell us with this? It seems deadset on depicting many intimate ties as unhealthy, too "inbred" in a sense. To me, it isn't accidental: it is part of the entire idea. It is part of a move to make romance in general feel disgusting by association.

Romance in Homestuck is not a complete nightmare either (in early Homestuck, Dad and Mom find each other and it is depicted as a touching romance, and of course Roxe x Kanaya is the poster child of successful, long-lasting love), but the overall landscape seems quite negative.

Consequently, I never thought Homestuck was SUPPORTING romance, quite the opposite, I perceived it as ATTACKING it.

Of course, attacking romance is not the same as being supportive (or even appropriate) towards aromantic people, but to me, it is worth mentioning, because I find almost direct REPULSION for romance here, a kind of feeling I know pretty well. And this is how I got this aromantic vibe from it. It resonates with me.