I don't allow rolling for ability scores, everyone uses point buy. Humans are still a great race.
On the suicide thing if one of my players ever tried to get their character killed I would oblige them and then ask them to leave my game, I don't want or need that kind of attitude at my table. Is this a normal thing in games that use rolled ability scores?
Absolutely. There's the spirit and the letter of the rules; ignore the former in my campaign at your peril.
And, if the DM says you start with 3 in every stat, then you start with 3 in every stat (just an example; I wouldn't necessarily do this, but then again, if someone pulled the "character suicide" stunt...). You don't get to quote rules at him and force him to aquiesce. You don't have to
like his interpretation of the rules, but if you want to play in his game, give his style a chance.
There seems to be a widely-held attitude on the net that players can hold DMs to the rules, and that "the DM has to allow this". I don't know when or why this sprung up, but it's not how D&D used to be played; rules lawyers were ridiculed in gaming magazines and official D&D products (e.g. 2e's Campaign Sourcebook). Hopefully 5e, with its emphasis on DM fiat, will change this, but sadly these attitudes seem pretty ingrained.
I was reading the other day about Dave Arneson used to DM. One of his players apparently whined that their character didn't get to roll dice in a particular encounter. He said "OK, give me a d6 roll every round". When asked what for, he said "that's the amount of damage you take". I thought it was harsh at the time, but I can see his point.