Thats up to the individual to be able to handle their drink. I can handle mine, I know when to stop, I dont get involved in fights, I dont drive, I dont look for trouble and all the rest.
But because some troublemaker chav either kills themselves drinking too much (in which case, good riddance) or looks for fights (which they'd do anyway), lets ban it and spoil the enjoyment for the rest of us who can enjoy a drink responsibly.
As for health problems. Yeah sure, if you drink too much, all of the time, you are asking for trouble. Drinking in moderation is actually good for your health, it relieves stress and stress is probably an even bigger killer than alcohol. If alcohol knocks 5 years off my life but I die a lot happier, then I'll carry on drinking thanks.
Edited to add, totally agree with Michael about the licensing laws. That would solve so many problems. Its already a bit better since there was a few bars open later in Newcastle.