I think that part of the reason the Yuridom went crazy for these two is because how unexpected it was.
Like sure, this is not the 90's, an openly and explicitly gay couple in media is not unheard of anymore, but whenever that couple are the protagonists 99% of the time it's slice of life and their gaynes basically IS the plot. And if their gayness isn't the main plot then it tends to stay as yuribait/yaoibait.
This series seems like it will be a break from that. It feels like I will finally get to have a gay anime couple plus an interesting non SoL plot. In a franchise as enourmous and influential as Gundam no less.
Feels good.