You didn't put "it may be consistent" you had "that would be a consistent position". If no 'divider' is put anywhere in this 'animal spectrum' (your term) then drawing on it for one comparison (euthenasia) has the same logic as drawing it for another (insecticide coated bed-nets maybe).

Having us as distinct from the animals allows an easy (for you - it drives most other people nuts) point of view. A lot of the human race (including many people of religion) seem to able to cope wih a more complex situation and make their own decisions (or maybe accept that of their culture). For example, we have vegans, vegetarians, vegetarians who eat fish, non-vegatarian who only eat animals that have had natural life. And so on.

Some of them squash moquitos, some don't. Some euthanase sick animals, some give painkillers to sacred (see - that word) cows until they finally drop dead (and wreck their eco-system in the process).

Moral decisions are complicated - unless you buy into an off-the-peg set.