It seems unlikely that eating lab-grown meat, for example, will be as efficient, in terms of CO2 emissions, as simply being vegan in a reasonable time frame. And it is currently not something that exists in a reasonable scale, so it’s not a “religious zealot view” to advance the current most practical, efficient, and easiest solution.

And some people who are vegan would not necessarily be against lab-grown meat, but it depends on who you ask