The original quote I remember is from P. J. O'Rourke, which is "When buying and selling are controlled by legislation, the first things to be bought and sold are legislators."

It's a caution against giving governments too much power to influence economic activity.

There are only two major reasons for private enterprises to attempt to influence legislation:

One is to gain perks and regulations that protect them from legitimate competition, "tilting the scales" and increasing their market position using government force. You'd be amazed at how many regulations exist for the sole purpose of protecting a business interest against competition.

The other is to try to protect yourself against the government using this power against you. "Protection money." Businesses that were once largely apolitical have learned that if you stay out of the Washington game, the game often gets played without you, and you find you've been edged off the field by businesses with less scruples, or legislators looking for donor cash on the barrelhead.

Sometimes it's some of both.

As always, it makes a big difference if you're initiating force or defending yourself. I really wish I could say that a lot more businesses are lobbying in self defense than in offense. But just from what I've observed over the years, that doesn't seem to be the case.

Of course, if government was separated from economic activity, for pretty much the same reason as it's separated from religious activity, there would be a lot less of this.