A lot of vegans eat fake meat and dairy which shares many of the environmental problems of meat, such as needing a lot of inputs so a lot of plant material relative to the final product.. It also adds energy use, transport, packaging etc.

There are also environmentally beneficial meats. So much so that when rewilding we sometimes need to add the same animals back (as is happening in Scotland - rewilders are breeding cattle that look like wild ones to make it "natural"). In the UK you can buy venison from wild animals that need to be culled to to preserve the environment.