The change log is a product. It needs to be reviewed, readable to the target customers, and compliant to any necessary contractual, legal, or regulatory disclosures with the appropriate disclaimers. It should not reveal any trade secrets, third party confidential information, violate any vendor NDAs, have any unprofessional remarks about the customers, etc.
It sounds like the problem is you're putting out crap change logs using an automated system to copy things from the issue management system. Do you have policies in place to make sure people don't put crap into the issue management system? Are things being reviewed before the change logs are being put out? Is it being vetted by the necessary product/legal/regulatory folks to make sure nothing is in there that is going to bite you?
If a company published a crap product, then it will get bitten. When a company gets bitten, it's instinctive reaction is to stop putting out change logs to stop getting bitten, because that's the easy, lazy, doesn't take more effort answer. Asking "Whether or not change logs are a good idea?" is the wrong question. The right question is more "Okay, we got bitten because we put out crap change logs. How do we stop putting out crap?"
The answer to that question is generally something called 'Hard Work'. If the company isn't willing to put in the effort to make a good change log (appropriate policies to capture the relevant changes, tech writer/tech doc support to clean it up, manager-level review to vet it for compliance, etc.) Then, yes, it may make more business sense to not publish anything rather than to publish garbage. It's not a matter of whether or not change logs are good or bad -- good change logs are good, bad change logs are bad. The question is: How do you generate good change logs?