Vegans object to all forms of animal exploitation, and raising animals to take their eggs still involves a degree of that. Even in the most benign cases of free range, well taken care of chickens in the world, chickens have still been bred to lay an unnatural number of eggs, which is very hard on their bodies, and that's being exploited by farming them for eggs.

For anyone who buys eggs instead, know that the animals are not kept in these benign conditions. Even 'free range' factory farmed chickens are kept in small enclosures, with only a small window to the outside. There are no store bought eggs that can remotely be considered ethical.