For those who don't know why people hate Epic Games, here's a short list:
The Epic Games Store (EGS) regularly pays for indie exclusives that were, at least in part, crowdfunded and were promised to be released on multiple game platforms
EGS has paid for exclusives from games that were listed for pre-sale on Steam only to have it pulled from Steam and upsetting all of the excited fans that wanted to play the game on their chosen platform
The CEO Tim Sweeney has publicly laughed at the idea of supporting Linux, and refuses to consider adding EasyAntiCheat (EAC) support to Fortnite until Linux allows kernel level anti-cheat software
To expand on the previous point, the EGS launcher has been shown to reduce battery life of a laptop by 20% even when the app is minimized. What the hell is it doing in the background? Nobody knows!
And expanding on the two previous points, a lot of people have heavily criticized Epic's $330,000,000 investment from Tencent -- the biggest gaming company in China that has been known to be very anti-consumer and anti-privacy
And although it's not entirely the fault of a new player in the industry, but EGS has way less functionality compared to Steam or even other games storefronts/launchers. Epic doesn't have community features (workshop, guides, etc), Epic doesn't have cloud saves, Epic doesn't have achievement support, Epic doesn't have proper controller support, and the list of features lacking goes on...
Nobody is saying that we don't want more choice of games stores. In fact, competition is good for the consumer! But Epic's practices have been wholly against the best interest of the consumer and providing a fair, competitive alternative.
Personally, I have never and will never buy a game from Epic. I'll take the free game and launch it through Heroic games Launcher which already - as a free and open source project - works way better than EGS with their billions of dollars of investment.