Eating worms for someone who is vegetarian for an ideological reason

As far as I understand, the brains of invertebrates (e.g. shrimp) are less developed than the brains of cattle, so presumably they 'feel' suffering less than cattle.
A person who is afraid to eat beef for moral reasons, because of the suffering the animals endure during farming, is it correct to say that eating seafood is less problematic (again, morally, not halachically).