Because:
They don't all play right now, but are taking a break.
Maybe you have 2 friends, and so this is easy for you but some of us find the idea of coordinating everyone we like to play with onto one server especially when they are randomized to be absurd.
This is beyond even just offering server transfers, this is dumping everyone off of their server and saying "pick a number, and if you don't we are going to pick one for you".
They are destroying communities, and maybe yours sucks. But I like my linkshells and Selbina. They should have just merged the crappy servers into the better ones and then let the anti-socials/trolls/outcasts opt for a server transfer.