Using tamquam to say “X is like Y” seems to be at least unusual, it is more typically used to form adverbial expressions like sensus in capite tamquam in arce conlocati sunt etc. (Even with esse, e. g. apud eum sic fui, tamquam domi meae.) I'd feel insecure about writing that. Instead, I would rather say similem melis venenati esse (or meli venenato): “to be similar to poisoned honey.”
Aside from that, all looks good to me.
I do remember the story a little different, though. Te fortasse, mi carissime Antoni, delectabit Latine me totam rem referre. Diogenes enim pro lupanari constitit quondam et appetentibus singulis dicebat: pulchram meretricem melis venenati similem esse. Scortatores, quibus scilicet talia verba displicebant, ut taceret, nummos cynico obiecerunt. Qui, simulatque satis pecuniae accepit, sine mora ipse lupanar intravit.