Theory A: Any species that evolves to the point of sentient intelligence will develop the ability to bring about its own extinction long before developing the ability (if such a thing is even possible) to travel or transmit information faster than the speed of light - a necessary ability to visit or even just communicate with other species across interstellar distances. Theory B: Every species that evolves to the point where it is able to bring about its own extinction, will.
Evidence: We only know of one species that has evolved to the point where it can bring about its own extinction - Homo sapiens. But we are no where close to figuring out (again, if it is even possible) how to exceed the speed of light. Theory A holds true for human beings. As for Theory B, it is clear that we are enthusiastically, gleefully even, doing everything possible to accomplish exactly that - bring about our own extinction. We’ve amassed enough nuclear armaments to bring about nuclear annihilation (and the two nations with the vast majority of those weapons are both currently headed by leaders unstable enough to actually use them), we have so badly polluted the planet we live on that many climate scientists agree we have already passed the “tipping point” where it no longer matters what we try to do - climate change WILL render the earth incapable of sustaining the human race in the near future. We have developed genetic engineering tools (CRISPR) that potentially give scientists and enthusiasts alike to either intentionally or accidentally engineer incurable pathogens that could wipe out our species. And who hasn’t heard over and over again recently about the latest existential threat to human kind - AI?
Conclusion: If Theory B is true (and I strongly believe it is) then the reason humans have never been visited or contacted by an alien civilization is that any such species that evolved before ours has already extinguished itself, and any such species that evolved concurrently with ours is working just as hard as we are at their own extinction and will accomplish that feat long before they discover faster-than-light travel or communication.