I'm getting this feeling that EA doesn't really have enough knowledge of the nuances in SWGoH to realize what a shard chat is and how it impacts the "pvp" element.
I took No_Try's recommendation and contacted EA customer service. I explained the concept of shard chats, how common they are, and shared my view on it. Then I asked for an official EA stance on the practice of shard chats in SWGoH.
I honestly expected a canned response, but the EA rep actually agreed that it seemed unfair. The most pertinent part of the reply was this (and I'll bold the line that makes me believe EA would consider shard chatting against ToS):
Please let me share that, your concerns, feedback and troubles are important to us. We want to thank you for informing us about the player, we will fully investigate your report. We strive to provide a safe, fun and fair place to play and commit to taking the appropriate action against those who wish to abuse Star Wars: Galaxy of Heroes in this manner and those who create applications or cheats which can be used to give an unfair advantage to a player.
They filed it under "Harassment" whereas I actually wrote the ticket under "Game Information" or whatever. Nor did I actually report a player, but the rep was speaking of it as a blanket investigation into player(s).
So... who knows, maybe that's just the copy/pasted response everybody gets.
But if someone feels they're a victim of shard chat targeting, I would suggest reporting the players, timestamps, etc, of when and how you think you're being targeted.
Alternatively, all you shard chatters who think shard chats are completely in line with ToS, put your account where your mouth is. Report yourselves and your fellow chat members to EA. Attach Discord transcripts and timestamps of you and other players targeting non-chat players and agreeing upon payout schedules. If your activities are allowed, then you've got nothing to worry about, and you can come into threads like these and say "see, I told you guys."
(FYI, happy to forward the EA response to anyone who wants to see the reply.)