You'll only bend the rod if you hold the rod by the bottom while you drive the pins out.

If you rest the piston on a pipe, or a deep well socket, you will not bend the rod because you are applying force in the same area rather than on the rod shaft.

I built and balanced my motor myself. I checked my rods on a marble table, with mics after removing my pistons. They were still straight. There's really no force required to put the pins back in if you do it the same way I did.