Yes, it is generally considered rude and a violation of privacy to walk into the bathroom while someone is showering or bathing. The bathroom is a private space where people expect to have privacy and the opportunity to attend to personal hygiene without being interrupted or observed by others.
Walking into the bathroom while someone is showering or bathing can make them feel uncomfortable, embarrassed, and invaded. It's essential to respect other people's privacy and boundaries, especially in intimate settings like bathrooms.
If you need to use the bathroom while someone is showering or bathing, it's polite to wait until they finish before entering. Alternatively, you can knock on the door and ask if it's alright to enter or wait until they signal that they are done. Respecting others' privacy in these situations is a fundamental aspect of being considerate and respectful of others.