I understand your frustration. Anyone who takes care with their research feels the same way.
Unfortunately, there is no one to "complain to." Ancestry certainly can't police family trees. I agree that they could present some basic warnings when someone is entering data. That might catch some real obvious errors - like "this child was born before her mother was born." But these kinds of error warning won't catch most mistakes.
Sloppy genealogy is not new. It has existed for many, many years. Back when our family trees were kept on paper. Remember that? However, the internet has made it much easier to find good genealogy records; it has also made it easier to find bad family trees.
And one more thing, those people that have such bizarre errors in their family trees will not respond to corrections or offers of help. So don't bother with that.
My suggestion? Either ignore family trees entirely and do your own research, or use them (very cautiously) for hints. Even in a bad family tree, a person might have correct information about close relatives. But even then you should verify the information from other independent sources -- coupled with a large dose of common sense.