Hmm, so I just saw the Snickers commercial for the first time (God bless Google), and I have to say, I didn't find it that offensive. I didn't really find it that funny, either. It probably could have been hilarious if it was better developed, but the one I saw was only about 10-15 seconds long (maybe it was cut/edited down).
As for the pizza commercial, it's kind of a dumb commercial (as many of their spots are), but it certainly didn't make me want to cry or anything else like that.
Honestly, bald jokes are going to be around for a very long time, just like jokes poking fun at any other non-terminal condition. There are just as many media portrayals of obese people, men, women, blondes, Canadians, Rabbis, sharpeis, etc out there. It's part of life. All we can do is work on our own self-images and learn that these commercials are far from being part of a malicious agenda set forth by some double-secret organization of "shallow women" or mean male models with a full head of hair. They're just something that apparently played well to a focus group. Nothing more, nothing less. A lot of people found it funny. Period.
That's the same reason that other groups mentioned (terminal illnesses, balding women, etc) aren't portrayed in this light: no one finds it funny. That's all. Not because we're being persecuted.
Yeah, it sucks to lose hair. I've been doing it since I was 18, and it's certainly not fun. But the truth is, I care much more than anyone else in my life, including my fiancee who knew about my hair when we first met and couldn't care less (she actually encourages me to go out without prothik, or to style my hair in ways that she likes, even if it means showing WAY more scalp).
Suing over these kind of things would be rather fruitless, I'm afraid. Most likely, it would have the same effect as the protest groups surrounding the film The Last Temptation of Christ: a lot of people flipped out, and in trying to boycott the film gave it massive free publicity.
My advice? Simple. Take care of yourself. Stay healthy, dress well, care for your hair. If you want to take finasteride and minoxidil then do so. But don't forget to also choose a style you love. Do what makes you happy. Hair is important, but it's only one aspect of you, both physically and mentally. Don't neglect the other facets of your being.
And if necessary, work on your sense of humor. It's going to be a lot easier to deal with these ads when you can see them for what they are: attempts at using humor in a commercially advantageous way.