I’m always surprised to see people dissing their previous employers in public, and it’s not something I recommend you do. I think it paints you in a more negative light than your previous employer.
People leave jobs for all kinds of reasons. Some people leave for better opportunities — that’s what I did last year. Some people leave because of personal issues not related to work. Some people leave because the job just doesn’t fit them anymore or because there’s nowhere else for them to advance career-wise within the company. Some people leave because of poor performance. And a very few people leave because of harassment and abuse.
But recruiters looking to determine if you’re a fit for their company don’t want to see you badmouthing your previous or (even worse) current employers. It’s not professional and it makes them wonder if you’ll be doing the same thing with their company.
Of course, you’ll never be completely happy with everything your employer does. There will be policies and decisions you disagree with. But don’t rant about them in public. Try to work internally to fix them, if you can — and I know this can be very hard in many companies. If you can’t fix them and you can’t live with those policies/decisions, maybe it’s time to look for another job.
There’s very little to be gained by complaining about an employer in public. Remember what Thumper said: If you can’t say something nice, don’t say nothin’ at all.