I don't feel single males need to be nueterd.
There is a low chance of health problems (Unlike females) and if he is already happy with no horomone issues, I don't feel any need.
I would not get my holland lop nueterd if it was not the fact I have 2 other bunnies.
They can smell stronger, so it is something to consider. They also may not use the litter box.
But having a single male who is behaveorial sound, I don't see the need. Just my two cents.