This is appalling, Tubas. I'm glad people have screenshots to provide evidence of such behaviour by Mermaids. It's outrageous. It is not, however, altogether surprising as the charity's reputation is very poor already among those of us who take an interest.
I remember during the whole Spartacus thing, MNHQ posted that, among other things, they were concerned that parents of trans kids might find MN an unsympathetic environment.
It's ironic that the real danger to such parents appears to be from Mermaids, a charity that supposedly "helps" trans kids and their families, or at least it does so long as they toe the party line.