why does involvement with EA imply being ethically challenged? i’m personally not involved, but on its face it seems better than not doing any kind of charitable work.

EA has a few branches of thought. One of them is "I am going to donate $X to charity each year. How do I maximize the good this brings to the world?" This group is sometimes less effective than they'd like to think, but there's no moral problem with it.

Another branch is "I make lots of money at a job that's probably making the world a worse place. How do I reframe this to not feel like a bad person?" They do some math and conclude that it's net more good for them to earn a bunch of money and donate some of it than it is to volunteer or it is to work at a job that isn't making the world a worse place. This is an awfully convenient conclusion as it means that all they have to do is pay a tithe and make no real changes to their life.

The notion of making money specifically for the sake of funding good things isn't a completely terrible one, but a vocal portion of the people who espouse it are very obviously not primarily motivated by maximizing the good they do.

> why does involvement with EA imply being ethically challenged?

Because almost everyone prominent in the movement has had some combination of lack of judgment and morals. There various terms for rationally pursuing philanthropy; associating with effective altruism involves embracing its ideas, people and culture.