It's precisely because the alternatives, delicious as they are, do not replicate the experience of eating meat. People like the taste of meat and they want to have it, that's really all it is. If you want to satisfy those people without incurring the environmental and ethical costs associated with raising and killing animals, you have few options besides replicating meat.

Or, portobello carpaccio with pecorino and truffle.

I'm not sure what the need is for the fake confusion. People like these items because they enjoy the taste and/or they are familiar. It's not at all hard to understand.

I've been a vegetarian for well over two decades. Growing up I was always completely grossed out by the concept of meat, so I almost never ate it before I went vegetarian, and didn't AT ALL enjoy it when I did eat it. For many years I didn't want anything "meaty." It was still obvious why people would want meat analogues, even if I wasn't one of them. I don't believe that these "I don't get it" comments are in good faith.

Around 5 years ago I started dabbling in fake meat. Turns out enough time had passed that I got over the icky-ness of a "meaty" product. Now I really enjoy a large variety of fake meats even though there's ALSO a large variety of vegetarian dishes I enjoy.

I want a burger, I don't want a mushroom sandwich. How is that so hard to understand? When I want mushrooms I will eat mushrooms. If random replacement was a viable alternative, I would just eat a fish sandwich.