Well theoretically, #vegans shouldn't have any objections against labgrown meat, at least not moral objections. But in practice, I think that they're so ideologically driven that they will still find some reason to keep pestering people about not eating meat. It's like some sort of religion, really.
Personally, I am neither #vegetarian nor #vegan, but I will switch to labgrown meat once it becomes affordable for both ethical and environmental reasons. I'm sure at one point, lab meat will eventually become even cheaper than organic meat, but the latter will stick around as some high-quality gourmet food.