But this attitude of looking for a fight, instantly boycotting anything to do with M&S, gleefully writing angry emails of complaint? This is all behaviour I associate with TRAs, and I'm not going to be part of that.
Any person, female or otherwise, should be free to boycott any brand or company they wish to, for any (or no) reason.
Similarly, anyone should be free to write a letter/email of complaint to any company they wish to.
If you don't agree and you don't want to boycott a company or complain to them, then that's fine.
But shaming other women into staying silent and not grumbling because you don't want to is intolerant and manipulative - it's a common tool of the patriarchy in keeping women down.
You can do what you like, but so can everyone else.