Re: plugin-template.php using member theme?
You are asking in a support forum why design decisions were made and why, considering the evolutionary nature of software, bp ended up as it did. As an end user of bp I have absolutely no idea how to answer either of those questions.
The real answer is that things don’t have to be like they are if you don’t want them to be. Come up with an enhancement and share it with us. That’s the beauty of open source under a GPL license.
Code is Freedom.