Well, one dead swallow does not break a summer. Vegan > not vegan is still a good first-order approximation; if you want to be more precise, vegan+avoiding palm oil > vegan > not vegan.
[1] - https://www.triplepundit.com/story/2015/earth-balance-switch...
Unfortunately one can also perhaps justifiably say:
eat insects > eating vegan > ...
And that makes it all the less romantic. Ideology to me has some merits, but I personally prefer to attempt to optimise at each point (including the meat production pointset).
EDIT: The Netherlands is setting some precedent towards this, especially for animals and improving their surrounds.