The full quote is this:

“Those who want to preserve freedom must ask for free trade, both domestic and foreign, for the gold standard, and for the reestablishment of the governments’ exclusive right to resort to violent coercion and suppression (this involves the abolition of the labor union privilege to “punish” strikebreakers).”

I think LvM is saying that extra governmental institutions have been given the power to act violently without restriction. For example, labor unions at one time (maybe even today to some extent) could prevent workers from crossing the picket line through legal and extra legal means. They could intimidate “scabs” — even physically harm them without suffering any penalty. LvM viewed this as a State’s monopoly of coercive violence being farmed out to private organizations. I’m sure Hoppe & Rothbard would have a different/broader take on that issue than LvM (i.e. no one should have these powers including government), but LvM was concerned that the power to commit violence was being extended from governments to favored governmental groups.

What M Conaghan said about two glasses could not be more clearer about von Mises concerns. Patrick Henry did said similar words, “Give me liberty or give me death.”

It is great to know what von Mises’ reservations he had prior to the establishment of the society. It gives me another peek in his mind, an absolutist in his principles.