Why is it not "On neni muz, ale kluk"? It seems like on (he) would be more appropriate than to (it) if you are talking about a person
"to" doesn't actually mean "it", it translates to "that" albeit the form for neutral nouns, not masculine ones. That is what confused me, why not use "tem" rather than "to"?
I would guess that "ten" has to appear together with the noun ("ten muz je..."); maybe "to" can appear alone...
This is the special and so confusing sentence type "To je", "To jsou", "Je to", "Jsou to...". You will find much morein the Tips and notes and many other sentence discussions.
Isn't the correct English equivalent "THAT is not a man, but a boy."?
That is also an accepted translation.