That’s kind of more up Jainism’s alley than vegan. I think most vegans are used to dealing with bugs being on veggies, and realizing that part of interacting with the world will eventually involve causing harm in some fashion, and it’s your job to figure out where and how to minimize it.
I don’t know a single vegan who goes out of their way like that, they all eat broccoli and cauliflower. I can’t say about kosher allowances, but with that line of thinking, flour wouldn’t be allowable either, as the FDA allows up to 75 insect fragments per 50 grams of flour. Cite: PDF from USDA. You can be quite certain any bread/flour/food that contains flour that you buy will have insect parts in it.
Well, the same can be said for lettuce, leeks, kale, chard, fiddleheads…where does one draw the line?
I’ve eaten more bugs by accident when I’m out running than I have in cauliflower, I reckon. Seems that wiring one’s jaw shut is really the only way to go.
Interestingly enough, the more orthodox Jains actually do wear a cover across their mouths for this reason. (I know a few Jains, but they’re not quite that orthodox.)