This argument doesn’t make any logical sense.
Your argument appears to be:
Some labour unions are bad/corrupt, therefore no trade unions should not exist.
You seem to acknowledge that some governments are bad/corrupt, but don’t apply the same logic to them. If the same logic was used it would be:
Some governments are bad/corrupt, therefore they should not exist.
However you instead apply the logic of:
Some governments are bad/corrupt, but they should still exist.
I just want some logical consistency.
I’m not arguing that there aren’t bad labour unions who don’t effectively represent their members. I’m arguing that the existence of bad/corrupt labour unions does not mean that labour unions should not exist at all.