I became a vegetarian because of the fact that animal production, particularly by intensive agriculture, is environmentally unsustainable.
One-third of fossil fuels used in the United States are used purely for animal agriculture and 2.9 million acres of rainforest land was cut down, in a year, to either keep livestock or grow crops that will feed factory farmed animals.
So, getting back onto why I personally eat faux meat, it is because:
1) I'm not a vegetarian because I 'find it disgusting to consume another being' or because I have anything against eating a 'dead carcus', it is for environmental reasons, so therefore eating faux meat does not affect me.
2) It gives me the protein that I wouldn't otherwise have in my diet.
3) Learning/cooking a whole new repertoire of recipes because I've given up meat is just time consuming and pointless, why not just throw some fake meat into something instead of actual meat? It's a good substitute.