I don't see why Brexiters should be silenced forever if they lose the next vote, no. We repeat other votes on a regular basis, and sometimes when the facts change, politicians and the people change their minds. Something as complicated as Brexit seems like a particularly bad idea to make an exception for.

If a subsequent Remain vote resulted in a similar situation where any real world option to remain in the EU would be regarded as a betrayal worse than leaving by a large fraction of the people that voted for it, I'd think another vote was actually necessary...