For your second question, you don't have to, of course, but the vegan philosophy is to reduce animal suffering and to improve emissions. If that is something one believes in, it behooves them to make more people follow their tenets.
Because.. it is not the same?
> vegan philosophy is to reduce animal suffering and to improve emissions
Vegan philosophy is not consuming food of animal origin. If someone likes to put some virtue signalling to it like reducing emissions and sorts that's fine by me.
On the first one, animal suffering has very little relation to do with veganism. You don't need to be vegan to do something about it and certainly being vegan doesn't make you reducing the suffering.
Vegan diet is not consuming food of animal origin. In French we would qualify someone following a vegan diet "végétalien" / "végétalienne" (vegetalian doesn't seem to exist in English).
But usually people have reasons to follow a vegan diet. Usually philosophical/political reasons. And those reasons are usually animal well-being and environmental concerns. that's when we start qualifying people "vegan" in French (though the words are are in practice somewhat used interchangeably of course). OP specifically said "vegan philosopy", they don't refer to the diet specifically, which is only one part of the package.
And virtue signaling is not always (rarely?) the main motivator, or a motivator at all. You need stronger motivation than that and people do not always act selfishly to show they are better. They want to actually be better (as defined in their perspective).
More important question here is whether lab meat objectively (and objectively is a key word here) has any benefits over traditional meat.
Wrong. This is literally the core tenet of veganism, so much that they do not eat animals whom we know don't have adverse effects on their psyche, such as bees' honey or clams or shrimp. If you are looking for those who would like such an effective boundary, those are vegetarians.
While I disagree about being same, I agree on it not being a plant based.
> In this way, you get people to become vegan without actually having to make them change their behavior
Why do we have to get people become vegan?