EGS can't compete on features for sure (it really is quite a shit platform), but they would be very competitive if their 12% fee (vs. Steams 30% fee) could be passed to buyers as lower prices. As it stands, Valve's policies essentially strongarms the market to prohibit this (publishers selling on Steam may not have a lower price on a different platform, or the game can be de-listed from Steam). The Wolfire v. Valve case is highly relevent here.
My plea is for you not to get mad at Epic for being shit. We should be accepting of crappy platforms if their fees reflect that (Epic charges 40% what Steam does). Focus your frustration at Valve for preventing the market from fairly allowing you select the quality of the platform you'd like to pay for.
It is very much not clutching at straws to claim that. That policy is a major element of the Wolfire v. Valve case. You can also look at how despite charging a 12% platform fee, Epic Games Store does not sell games 18% cheaper.
It's an abuse of Steam's established market share and consumer habits to coerce publishers into not offering consumers a fair price on other platforms. It very literally stops EGS from competing on price, which is pretty much the only area where Epic can beat out Steam, since Steam otherwise is much more convenient, provides more functionality, and has more community-generated content (i.e. workshop material).
It's hard to say that isn't anti-competitive, especially because such a policy is only effective due to Steam's existing market share.
This is a fair complaint against Epic, I agree.