I've been self-employed for some 25 years. I say that to let you know that I have nothing against sales, marketing, or making a profit.
But there are certain areas of life that are outside the arena of sales. Family, love, children. And church. Within the Divine Service (the Mass) there should be no hint of selling, of trying to persuade us of anything outside of what God's Word tells us.
Practical implications? No politics, unless it is something with a clear (think, say, abortion) mandate from Scripture. Especially no politicians there to speak. No nagging about environmental issues. (A local minister preached a sermon on which car he thought Jesus would drive. He concluded that the vehicle in question would be a Volkswagen bug. No comment).
This is one of the reasons why I'm opposed to "patriotic," national day celebrations or recognitions (e.g., Independence Day, Veterans Day, Memorial Day) within the service. Not that it is necessarily wrong to recognize these days, but because they have been hijacked in the last few years in the service of politics. This is a problem that comes and goes in American history. In the last few years, the right has come to use patriotism in the service of electoral politics, while the left has done so at other times. But this just doesn't (for a number of reasons) belong in the Service. Not even close.