They aren't manipulating anyone... they're just making it known they'd prefer not to be linked to from another platform.
Is this a reasonable expectation? I'm not sure -- my gut says probably not. Is it a reasonable request? IMO yes.
Contrived scenario for expository purposes: lets say I'm an expert in pre-civil war era southern cuisine. If I find out that people on stormfront are linking to and discussing my posts for their own agenda, do I have a right to make them stop? Of course not. Is it reasonable for me to say "I'd prefer if your platform didn't link to my blog"? Of course it is.