It does, but BL is just a way of saying gay relationship and doesn't have a distinct definition. A one sided relationship isn't BL... but some can consider the attempts to be BL. As the attempts are gay, but the relationship isn't. The problem is term gay isn't as commonly used as bl in order to distinguish what gender of gay they are. As such it requires context.
Unless it is enemies to lovers (it should be), then a relationship like that isn't BL... it's just the one gay character trying to have some boy's love
