Sometimes I just want something that tastes like meat. I ate meat for most of my life, and I do miss the taste of it sometimes (though less and less over time). But Gardein fake meats usually scratch that itch -- I like Beyond Meat, but they are way too high in calories for me.
It depends on the brand, but a lot of them are actually plenty healthy and a lot lower fat. The Beyond/Impossible ones are basically supposed to be 1-for-1 recreations of actual burgers or whatever, so naturally they're chock full of fat.
The point is protein. Wheat gluten and soy products are meat substitutes for their protein value. Dairy is an option for vegetarians who are not opposed to animal products, but vegans shun it.
Half of my family eats meat. These meat substitutes are a way to get us all eating the same meal without anyone complaining. If we didn't have these, then on the nights when someone wants to eat a burger, a sausage, a chili or a pasta dish, they'd be eating meat. So while there are still stubborn meat eaters in the household, these products help reduce our overall meat consumption by providing an easy option everyone will eat.
Just because there are ingredients listed it is not inherently bad and these products are targeted and mostly consumed by people who want to eat less meat or miss it. There are people who want to eat less meat because of ethical reasons. Regardless of the reason, whatever helps people eat less dead animals is a good thing.