First, vegetarian diets are not for everyone. If they are so wonderful, how come people so often have to take supplements to make up for things like B12 which they can't get thru veggies? And why should we assumew that supplements are the best sources for our needs, rather than natural ones? Rhetorical Qs.
I know that many people don't go by the Bible, & that's their choice, but I do & in it meat is a staple of the diet. To me that says it is generally going to be necessary - but again, different people have different kinds of bodies & requirements.
2nd, yes, it is not as simple as killing parasites & yes they can multiply quickly & you need to do the other kinds of cleansing too. But to ignore killing the parasites, and I mean ongoing fighting them every day, would be totally foolish, even potentially very deadly, in my humble opinion.