Oh, Rumil has nothing against Glorfindel - he was being his tongue-in-cheek self, I fear. He doesn't think the twins would be very happy if she decided the thing she most wanted to include in her new home was Glorfindel - if he turns out to be what appeals most she will, sadly, have to leave him in Imladris...

Glorfindel will certainly broaden her education... with a sword.

But other aspects of it might well be broadened by others - without it being close enough to distract Rumil - which some of the broadening just might have as they have 'an unusually strong link for a couple not yet betrothed'...

She'll doubtless have time to think of another story or two for the next time she's asked!