When they added microtransactions and lootboxes I grit my teeth and accepted it, knowing it would be a necessary evil to support the game.

When they started adding zed variants I thought maybe this was the start of something good, a step in the right direction with added gameplay variety.

Then they started to ignore feedback and made zed variants progressively worse as they released them with broken hitboxes, unfair gameplay mechanics, and generally ugly designs that stray too far from the original art direction; EDARs are not fun, they are not zeds, and they break the flow of gameplay.

Then they added a player versus player mode that nobody, nobody, asked for. Wasted developer time and resources.

Then they started to add uglier and uglier cosmetics to their pool of microtransactions and bloat the lootboxes' drop pool with alternate colored variants of said cosmetics, which also bloats the users' inventory. Got a specific item you want from a lootbox? If you do manage to get it you likely won't receive the color you want. You gotta open up another lootbox or buy it direct from the market for an inflated price.

And then comes the kicker, the promise breaker, the $10 weapon microtransactions. $10 for a SINGLE gun and 5 skins you most likely do not want. They promised that no gameplay additions would cost money and then they pull this out of the Abomination's filthy, unwiped posterior. Imagine being the person who decided a much requested weapon that's been asked for since SWAT was added in 2016, should be sold for $10.
Edit: After doing some digging I could not find any evidence of Tripwire stating they would not add paid weapons, whether through DLC or microtransactions. See the comment section below for more information.
This does not, however, change my opinion on paid weapons in Killing Floor 2.

I cannot recommend this game if you are against microtransactions in full priced games.
If you're someone who doesn't care about any of that noise there's still a playable game there. Just don't give them any more money beyond the initial $30 price tag.