Full Idea
If someone acquired a taste for poisons which would kill him or make him wretched, it would be absurd to say that we ought not to argue with him about his tastes.
Gist of Idea
If would be absurd not to disagree with someone's taste if it was a taste for poisons
Source
Gottfried Leibniz (New Essays on Human Understanding [1704], 2.21)
Book Reference
Leibniz,Gottfried: 'New Essays on Human Understanding', ed/tr. Remnant/Bennett [CUP 1996], p.201
A Reaction
This seems to be a first step in any discussion of taste on which you would hope that sensible persons would agree. 'It is just a matter of taste' is definitely not the end of discussion. Aesthetic taste is important, just as values are important.