You seem to have no idea of how software development on a larger codebase works. Not in theory nor in actual reality.
Quote from the steam page:
Being rude doesnt help anyone. If you are unhappy with the state of things come back later.
If you understand that MP is not in the focus atm then you can expect bugs & crashes with the amount of changes they make.. Yea it would be lovely if it would be stable but its not and wont be for some time. The devs work hard at it.
If I was wrong and you actually have any idea about development you can maybe influence that progress yourself:
or as a user try to be useful: report bugs etc.
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or their resources are spent on different areas other than your particular problem.