This discussion has been had to death on this forum, so at this stage I'll assume the argument is in bad faith.
Ultimately most PC users support multiple stores, it's the best thing about PC. Where problems justifiably occur is one service is not actually providing additive value or competitive service to Steam, so why should folks "have to" buy there when I can instead opt to buy elsewhere later, or as in most cases, get carried away with competing games instead.
If I buy in Steam, over a decade of evidence and trust shows I will get additive features and value to that game purchase as they evolve PC gaming in their ecosystem, as well as off the bat functionality I require and prefer. From streaming tech, controller support, Steam Input, BPM, library management, Steam Play/Proton, community, guides/forums, user reviews, workshop, SteamVR, reliable support services, etc etc, the offer is substantially more valuable and best for perpetuity.
On EGS, I have games I can't even access in my library due to activation issues on going for months, DLC that can't even be activated correctly, we've seen security issues, they haven't met their own targeted goals for development, actively opted to block customer focused open comms via forums and user reviews for specific triage, and still hasn't got the most basic utility for a baseline of gameplay I'd want. No. I don't need to buy specifically from EGS because it is justifiably a waste of my money. Anyone who is happy just to receive their executable as a one and done thing, EGS is great for them.
As for the comment now highlighted, surely that's on individuals and how they choose to support companies. I've seen equally aggressive comments for PlayStation and Xbox users on this forum. Up to them if that's how they feel. Can't say I feel the same way. But for example I made similar choices - after bad times with BF3 in 2012, we dropped Origin and I didn't play an EA game till Fallen Order since Origin wasn't a good experience for us and fell behind. Same with Ubi games at the moment since they are restricted to that client that isn't reliable.
There are sooo many games already and so little time for gaming for me, that it's absolutely trivial to make the 5sec decision to avoid games stuck in limited ecosystems/clients, and go for the other game I wanted that is available on a better service driven platform. In the end it's often tthe case that I don't get the games even when they do come to Steam simply because I've moved on to other games. And I'm certainly not the only one with this approach as shown with the CCU from the publishers that delay their launches from their initial marketing push. It's why lots of developers/publishers rightly try to support as much as they can as a multiplatform/store endeavour. Ultimately though, a good game will still sell if they can market it properly to grab user attention and they are happy with the service offering
I'm more than happy to buy of trusted services even if they lack functionality, but usually only at a disposable price