It is nice for everyone to say "they should be better parents". Problem is there are no parent schools. Being a good parent is hard, and probably does not come naturally to too many people.
I am an ok parent, but I'm certainly not fantastic. My personality is one that makes me avoid confrontation, but being a good parent means you have to confront your little beast
at times. I have had to do things that are counter to my personality to be a better parent.
Having said that, I have yet to take my child to a restaurant at all (out for coffee/milk shake yes, but full on meal no). I don't do McDonalds (very often) or the like because the food is generally shit - why should I go there? More often than not we eat at home - so there is no real issue, or we go to kid friendly places... He is only 18 months old, so not really ready for a proper sit down meal yet either
My point is - it is fine to be high and mighty about how other people discipline their children, but that doesn't make good parenting easy.