Why wouldn't a source be reliable?

No.

___________

This site can be reliable if the answers are coming from a person who is degreed, or licensed, or certified, or has extensively studied, or, at the very least, some experience, in the particular field in question. It's usually fairly obvious who these people are in relation to the answers given here.

__________

User-generated answers can be quite useful but should notbe treated as reliable sources.

By the way, it may be obvious that some answers are inaccurate or plain nonsense but it is much less obvious who is and is not 'qualified' to answer.