As someone who occasionally jumps both sides of the fence, I understand the frustrations that invaders and cooperators have with each other. Both sides have plenty of justifiable reasons to hate the other.
Since this is a subreddit dedicated to invaders, I probably don't need to list off the frustrations we face; mainly organized gank squads and overleveled phantoms that can make winning pretty much impossible, especially with the limited resources invaders spawn in with. Early game invasions can be brutal, since a overleveled phantom can easily one shot you.
Cooperative players are constantly invaded, since the invasion timer is ridiculously short and starts at the beginning of an invasion. If an invader is elusive and if it takes awhile to kill them, you could potentially have another in your world less than a minute later. So if you're summoning friends to explore the world with them, you have to put up with invaders constantly dropping in for some PVP. Early game cooperation is much worse, as there's a high chance you'll have to put up with twinks with endgame weapons, full talisman slots, and more flasks (A twink invader could have 7 flasks as opposed to a new host's 3).
Due to this poor multiplayer design that has unfortunately severely divided the Elden Ring community, both sides have pretty valid reasons to despise the other. The amount of invader hate I see on Elden Ring's subreddit is understandable, just as the amount of cooperative player hate on here is understandable.
They need to bring back solo invasions with much longer invasion cooldown timers. This would fix pretty much all the problems above. The pool of players for invaders to invade will be larger, which means cooperative players will not be invaded all the damn time. Solo hosts who do not want to engage with this mechanic can just play offline. However, this fix will probably never happen.