Fine for those who want to participate.
Sometimes they do end up in flaming matches which can bring out the worst in people. It's difficult sometimes to really express yourself on the web & often something that was not meant offensively can appear so... there's no body language & it's harder to get the 'tone' right without an actual audible tone!!!
The best example of this is when something is said (typed) that is sarcastic... several times I've seen peeps get the wrong end of the stick (myself included

) and get offended, when something was not at all offensive.
Whilst these topics do have more potential to get out of hand, I don't think they should be automatically locked: provided they stay on track & do not degenerate, it can be very interesting to hear other's point of view, especially participating in a forum than has such a diverse membership. It can be an eye-opener
I guess these sort of topics must give the mods a bit more work to do... after all, they're topics that can evoke very strong emotions in folk!!!