Turn down a job for any reason you want - you have nothing to feel bad / guilty about. But honestly, don't go into detail / give that reason. It sounds unreason

Turn down a job for any reason you want - you have nothing to feel bad / guilty about. But honestly, don't go into detail / give that reason. It sounds unreasonable, and could hurt your reputation (people tawk). If you have a long enough career is Software Dev, you will almost certainly at some point end of using a software product you personally don't like. Learning to compromise / pick your battles is a career skill like any other. Apologies if this sounds overly critical, but as a hiring manager, I would consider it a bullet dodged. Drawing hard lines in the sand over small things like this would be a red flag for me.