This is not a common experience, you shouldn't be so quick to make it the basis for your decision. Look how many DeWalt, PC, Milwaukee, etc. tools get sent back because of some problem right out of the box. Stuff happens. There's a lot of stuff to stay away from at Harbor Freight, as has been stated here many times, but there is a lot of stuff that is perfectly serviceable and saves quite a bit of money.
The clamps have a lifetime warranty - why not just send the defective clamp back?
How many other ones did you buy at the same time, that came out of the box just fine?