I think everyone has sympathy for these people, don't confuse discussing something logically with you as having no compassion for them.  Certainly there are plenty of people who just didn't know not to keep bitcoin on an exchange even though it has been stated by many hundreds of times - in fact I know a technically adept guy who had a few bitcoins at Gox because he just didn't get around to moving them.  Stating the fact that if you don't have the private key, you don't own bitcoin, is trying to help to educate people to the benefits of bitcoin. 

It is always best to educate yourself prior to investing, and a lot of people did not investigate Gox enough.  I've been telling people not to use Gox for more than 18 months because they just seemed inept.

Regarding this:

This is true, but we aren't there yet.  This is like the internet in 1988.  Some people were using it, but it was not easy to use telnet, ftp, and gopher for the average grandmother.  It wasn't for another 10-15 years - maybe 5-10 years after the web became available - that it became pretty easy to use.  Ease and safety will come.  Things like ardware wallets so you don't think you need to store BTC on an exchange, easy, more reputable exchanges.  (Just think though if the USA hadn't had a $20+ million cost to set up an exchange due to all the rules and regs for almost 50 states (iirc 2 don't need a license), Gox probably would have had better competition years ago and not gotten this far!)