They call it competition, because you can win some prizes at the end of the day. That's the definition of competition is it not?
Since they are not some big organisation, let's cut them some slack and just understand that they can't afford to pay photographers to take photographs for them. They are already struggling to keep the animals fed and taken care of. I understand this forum is rather particular abt the T&Cs of competitions but I'd see this one as helping a non-profit organisation out. I'd donate the money without any return anyways, so the chance of winning something is an added bonus.
This is also to raise awareness abt being responsible pet owners, which is sorely lacking in our society.