The interest and affection we have for pets is a very different situation than that of an intergalactic civilization's view on intelligent life. If they respect other life, intelligent or not, in the galaxy, chances are they would be very unwilling to interfere. I'd be very excited to visit a planet with other life on it but I would give an extreme amount of thought about whether I wanted to risk introducing pathogens or exposing an intelligent civilization to knowledge and technology far beyond its time (the immediate philosophical and psychological impact of discovering that you are not alone in the universe cannot be predicted, especially with alien races).

If, on the other hand, they didn't respect other life not as advanced as them, why would their actions be any different than that of humanity for thousands of years when dealing with less intelligent life forms?