I know someone close who actually was a negotiator for the local union, some years ago, who might well agree with you, today - as he's a small entreprenuer (racing business).
But I, who have never worked for a union, would still remind anyone that there has to be a balance against management who are not always the sharpest tacks. And a fool can easily reduce a man to time-motion studies and a 'burden on expenses/costs', etc. And a lot of b-school bred management are just that stupid - watch any group of these contestants on Trump's contest show to see for yourself.
Not all unions are the same. Not all union members are slackers. I'm sure many are. But I've seen public sector employees, essentially clerks, put in long hours for no money, and apparently for no other reason than professional pride and the idea of good service to the public. Amazing. And other union members, some, might do just the same.
If there's a clubby, clannish cynicism seen even in the hiring process, then I suppose it sends the message that work is for suckers, and collecting lawyer's pay for goofing off is what 'work' is. But again, not all unions are the same. Without unions, I see little that would protect workers who cannot lay claim to being key people. Most employees are not key people, and can be replaced, sometimes easily. They are at a disadvantage in that negotiation. And a union can help give them at least less of a disadvantage, if it's a good union that doesn't overlook the treatment of even one member (many unions do overlook such).
Conversely, there's really no excuse for sweetheart wage deal where unionists are known, citywide, statewide, for being grossly overpaid, typically of course from taxpayer, and often property tax! payer, dollars. It's obscene, abusive, and leads people to hope that the villians get theirs. A union doesn't have to be seen like that. Too many are.