I'm willing to go out on a limb and say unequivocally "You will never need to reinstall Solaris to install Perl 5.x.x". If they persist, ask them for their proof and bring it back to us. I feel very comfortable that we can provide answers that will satisfy.
Being right, does not endow the right to be rude; politeness costs nothing.
Being unknowing, is not the same as being stupid.
Expressing a contrary opinion, whether to the individual or the group, is more often a sign of deeper thought than of cantankerous belligerence.
Do not mistake your goals as the only goals; your opinion as the only opinion; your confidence as correctness. Saying you know better is not the same as explaining you know better.