The way they wrote the end of the Shadowbringers story, this became a mandatory story beat(or necessary evil if you dont like it). You are free not to like that decision, but it was never yours to make. Ill go into a spoiler block for a sec, just incase.
Time travel always complicates storytelling. When they started ShB, they werent sure exactly how they were ending it. As such, they could get away with the recommended but not required bit. If you hadnt done the raids, then the Exarch says that its something you would do in the future. You doing the raids at some point is required for him to exist, but him being from the future means it didnt matter when you did them. Then he ended up being a super popular character, and they decided to add him to the scions team going forward. The end of 5.3 sees you reopening the sealed tower, and reawakening G'raha. You cant reopen a tower that you never opened/sealed in the first place, nor can you awaken someone who hasnt gone to sleep. And while the workaround of 2 dialogue options for certain scenes worked ok for 5.0, you cant write a whole expansion with 2 versions of every scene that include and exclude a major character.
So since they forced themselves into making it required, the only question is when the roadblock should go up. You can argue if you like, but it makes sense that a level 50 piece of content that you need to do should be done with the rest of the level 50 parts of the story. Which is pre-HW - where they put it.
And as a final note Dani, maybe refrain from putting your personal feelings on to all of the "10's of millions of people who quit". Ignoring how many of those are RMT accounts that were banned(and then remade, and rebanned, and on and on), i think i can safely say that most of the people who quit between 2014 and 2018 didnt do so because they were afraid the CT raids would be added to the story-required instances at some point in the future.