With the correct science, the speed of light isn't an absolute. And if your science is advanced enough, getting around that way would be no problem. With that being the case, aliens probably find us interesting. So they come here to study us. It isn't much different that some zoologist traveling deep into the Amazon jungle to study life forms. And quite possibly, discover new species. Next, aliens are no doubt smart enough to know the value of limiting their population. For example, I saw a factoid once that said that if human population was to keep growing at the rate it is, in the year 11000 the human population would number 1,100,000,000,000,000,000,000,000,000,000,000,000,000,000,000 people! Even if they had places to go, I doubt that any sane alien race would allow their population to go beyond 20 billion.
As for the speed of light, there are things that are said to greatly surpass it. There is supposedly slowpoke jets given off by the collision of two neutron stars that go around 7 times faster than the speed of light. Then there is quantum entanglement. The connection between a particle on Earth and a particle in another galaxy would be basically instantaneous. By the way. Did you know that the math used for all electronic devices is quantum mathematics?