if the software is good and works to your benefit, why not use it?
sometimes people just don’t feel comfortable using work of someone who opposes their rights. even just using the product gives the creator more exposure, recognition, possible funding in the future if it gets big enough, and so on. so, if the creator is openly transphobic, for example, trans folks won’t want to use the product, and doubly so when the community around the product is toxic, too. they’re voting with their feet.