I don't straighten my hair, but... I think it is fair to say that everyone agrees that almost nothing you do to the hair strands themselves can affect your rate of hair loss.
Everything is happening under the skin, in the roots, anyway.
Many women report permanent hair loss from overly harsh perms. And tight braiding over time can damage follicles. But yes, anything you do to the strands themselves once they're outside the body will not accelerate male pattern baldness if you're not damaging the subcutaneous follicles.
man, I wouldn't do it. Some pretty harsh chemicals to actually make a hair straight. Never done it myself but I imagine that it's almost impossible to fully avoid the scalp....
It costs around ten dollars to have a stylist do it and they use conditioners and light chemicals. It won't ruin your hair. I've done it multiple times.