We live in a world where being an aggressive man isn't attractive so much. In the early 1900's it was "the bees knees" or whatever, but on through the disco era, into the hair metal, drug-fueled era and into the really, really bad apples that ruined it for everyone else era.....it's just better to not be the aggressor. It doesn't help that such kinds of guys are in the media so often and making it worse, still.
Worst-case-scenario, as you sit and wait for someone to approach you, the time it takes can be spent on seriously studying folks in the room. That alone can help you spot potential red flags and help you a lot. I don't just mean spotting red flags in your mind, but you can sometimes tell what another person's red flags are by how they act with others. Practically half of all that any relationship is, is two people figuring each other out. This approach gives you a head start.
Also, and I'm sure others are reaching the same conclusion, the direct therapy that you probably want to go for / focus on is anger management. It's not something strictly for total a-hole grumps and such. It's a process that helps even those who are traumatized by rejection, and I think it's clear that you lash out as a trauma response. I'm not saying you do it purposely, either. When people are hurt and treated with crap attitudes to a traumatic level, that person will start to act out with a crap attitude at the first signs of perceived bad treatment every time - it gets to be involuntary - it's the mind's way of thinking it won't be the victim, if it is instead the aggressor. And that just brings all of this back full circle. It's right back to not being (so) aggressive.
I know you tire of trying so hard and taking so much time to get where you want to be...but it's the non-negotiable part of any of us getting what we want (or even what we need). We have to put in the time and the work. You will always find that you feel better doing so, too because you'll know for a fact that you absolutely earned it.