Be a parent.
It almost seems as if many of these parents want a utopian society where their kids can freely live without ever facing offensive material or tempting problems and that actually raising a child will no longer be a burden.
Well, none of us have a choice, either as to what our local retail stores carry, now do we? What? Or are you trying to tell me we have no choices on water? (I think the companies that sell you water would beg to differ with ya, as would the survivalist/pre-Y2K companies that were selling various means of purifying water). So, your "flawed" angle is faulty on two premises.
Be a parent
Be a parent as part of a broader village. Just 'cause Hillarious attempted to co-opt this term doesn't dilute the fact that we are meant to act in a corporate manner on behalf of our young folks. Western cultures--particularly the US--are the most independent individualistic culture(s) the world has ever known.
These t-shirts are only one flow of moral pollution among countless streams. The bottom line, tho, is that they all add up to desensitizing boys/men to the real value of women...
I saw this last night in the 3 minutes I watched 8 Simple Rules on ABC...they had the entire class laughing off the teaching of abstinence as though it were an ancient myth.
If you lived in Sodom & Gomorrah, it didn't do any good to live in a righteous household when that righteous household was under threat of rape. So, tell me, what good does it do to rely on the doctrine of "If you don't like it, don't buy it" if you have rapists in your neighborhood fueled by many streams of moral pollution? Oh sure, your daughter may be protected from wearing such t-shirts, but not by the perps whom you ne'er raised any objection to what was being fed them by the companies you invested in.
Frankly, I have a problem with the kind of folks who conclude, "Don't like abortion?--don't get one." Those folks miss out on the corporate community consequences of murder (Deut. 21:1-9; Eze. 9:1-8; Numbers 35:33; Isaiah 26:21). As they say, if you're not part of the solution, you're part of the problem.