You have to separate the practical from the emotional reasons why this is bad.
When the Yankees played at Shea, I as a Yankee fan didn't care aboout the symbolism because, as has been noted, I knew it was temporary while YS was getting a needed renovation. But as a young teen living in Yonkers, I could get to YS in 30-45 minutes and Shea took 90-120. I went to almost no games those 2 years as a result. Which was fine because I had not prepaid for a slate of tickets more than 12 months previously only to have the relocation announced a month before the season started.
Symbolism aside, unless you live in a few Manhattan neighborhoods, getting home from RBA late night or on weekends sucks. People have season tickets they paid for more than a year ago and are just finding out they've been committed to making that trip regularly with no info about refunds, credits or anything. How will allocations work when 90% of STHs ask for every YS game and 0 RBA games? There's still no info available. Put aside NY/NJ symbolism, that sucks.
WRT the symbolism, I have always been an outlier in that I find the whole NY/NJ thing WAY overdone. BUT, it matters to a lot of people, the club and league have known this from before the expansion announcement, and marketed on that basis. Add in the club history of deception and poor communication: Lampard, ending paper tickets, the 2019 playoff Citi Field seat assignment nonsense, the 2020 Citi Field seat assignment repeat nonsense. I can't even keep track, but there were more, and with every one you have speculation, denials, a last minute announcement that confirms the speculation and renders all prior statements outright lies, accompanied by no apology and if there's any explanation it is of the "what did you expect, you were fools for believing us" variety. Add in the never ending stadium saga, which we barely even talk about any more we've gotten bored with it, and yes, there are fair excuses but again, they sold something different. The whole Founding Member wall promise is a bad joke. The idea that anyone reasonably believed that to make the Wall you could maintain tickets for six years and not even have a site announcement on the horizon is absurd. In retrospect, the 2018 focus groups were just an expensive dog and pony show to make people think something was imminent when clearly it was not.
People are understandably frustrated. How will the club handle scheduling and multiple stadiums once the pandemic ends? There's no reason to expect anything good. NYCFC might handle it well, but there's no excess, reserve goodwill left to make people want to give them the benefit of the doubt. And as always you have 3 choices, walk away completely, remain a fan but with decreased engagement and/or spend, or suck it up. And both options 2 and 3 just keep punching you in the face.