This is a problem with your mentality.
There's 4 green modifications in the game: CA1-3, KI1-3, Flak, and Fragile.
Kevlar is bad because mobility in this game is incredibly important and the value of health is weaker than the value of movement speed.
Fragile is niche/bad because it leaves you overly vulnerable to certain match ups and the diminishing return on MS isn't typically worth the cost you're paying to be one speedy boi.
Flak Jacket is niche and costs you a grenade, which is a very high price to pay for arguably one of the most important elements in the game.
So that leaves you with CA; which is effective most of the time compared to the rest and the cost is reasonable enough to swallow without too much fuss.
Does that make it "overpowered"? I don't think so. I think that makes it the only viable option to run in your kit 95% of the time. That alone doesn't make it broken, just means there needs to be more options or improve the others we already have and make them more viable. This is presuming that LO even wants this to happen.
You're self aware, at least on one part at least.
If your posts are getting tonnes of negative feedback, maybe stop and ask yourself why. Maybe, just maybe, consider that your view is wrong or not in the best interest of the game as a whole. I'm not saying you shouldn't have these opinions, because that's what having an opinion is all about, but perhaps not reacting with surprise that your opinion is nowhere close to everyone's opinion, so there's going to be a lot of people who disagree with you.
And when that's true, they're going to let you know that.