I think that's a fairly tasteless comment, really -- historically it would probably be wrong, anyway, and I don't think that most world leaders in the past, including Tony Blair, would be discouraged from doing what they thought was the right thing if that would put their family at risk. Indeed wouldn't it just be another way to criticise him? "Oh, you only care about your own family and not about anyone else"?
I also struggle to understand the "we aren't the world's police" remark, if it comes to that. Granted we can't cure all the world's ills. But that doesn't mean that we shouldn't try. The problem in the past was that we went into Irag and Afghanistan and then apparently had a seriously bad plan to rebuild the country after toppling the ruling regimes. That could end up making things worse, if that's even possible. On the other hand, ignoring the mess in the region is unlikely to lead to much better. As I said earlier, the situation will not stay confined to the region for long.