I think people are outraged not because it's illegal, but because it's unconscionable. I think the general understanding is people shouldn't have outside-work activities be held against them, maybe it's time for the law to catch up.
It's pretty easy to come up with a lot of absurd and "legal" at-will policies (e.g. we'll fire anybody who watches porn)
It's pretty easy to come up with a lot of absurd and "legal" at-will policies (e.g. we'll fire anybody who watches porn)