Who really cares about people, cares about animals, too, and who really cares about animals, is also concerned about people. Ethics are not divisible.
Humans come first is a cheap and mean pretext for doing nothing, either for animals or for people.
You cannot free slaves or emancipate women or accept homosexuals or protect animals. In real life a division of tasks is reasonable and obvious, as in the whole sector of non-profitmaking activities. That is why there is nothing wrong if some people concentrate on the interests of animals. In many fields love for humans and for animals can in any case go together very well. Maybe we can accept that as a behavioural rule in case of conflict.