Because the Praetorian guard spent lots of time beating the crap out of union members?
Oh, no, they didn't. The Pinkertons did.
Neither has been seen in person for quite some time. There's a much more contemporary anthology of violence committed by members of organizations that still exist here:
"Since 1975, the National Institute for Labor Relations Research has collected more than 9,000 reports of union violence. These incidents are recorded and electronically maintained in the Institute’s Violent Event Data File."
"West Virginia miner shot dead for working during a strike
On the orders of the United Mine Workers (UMW), 16,000 miners went on strike in 1993. One subcontractor, Eddie York (who was not a UMW member), decided it was important to support his wife and three children and crossed picket lines to get to his job. He was shot in the head as he left the job site to go home. UMW President Richard Trumka (now Secretary-Treasurer at the AFL-CIO) told The Washington Times that "if you strike a match and put your finger in, common sense tells you you're going to burn your finger." UMW strike captain Jerry Dale Lowe was found guilty of weapons charges and conspiracy in York's death, and York's widow Wanda sued the union for her husband's wrongful death. The UMW fought the lawsuit for four years, but settled with Wanda York only two days after federal prosecutors announced that they would share evidence from the criminal trial with York's attorneys"
Etc, etc, etc, etc, etc, etc, etc, etc...
Yes - dainty little things always on the side of the angels, those unions.
Why don't you have a nice lie down.