Back during my stint in the industry as an assistant pro, it didn't take long for me to realize that it only took one single, solitary really slow player to back up the entire golf course. A group is only as fast as their slowest player allows them to be.
It was, indeed, sometimes confrontational. I didn't tolerate slow play. You either pick up your pace and catch up with the group ahead, or the next time I come out - you pick up your balls and move to the point where you're in position.
The PGA Tour doesn't enforce slow play. They've made it known that it's not an issue, to them.
So although I chide players like Furyk, Holmes, Jason Day, etc... they play slowly because there are no consequences.
The European Tour is seriously considering a shot-clock standard, where it doesn't impact the entire group - but the slower players in the group. Capital punishment in that situation simply isn't fair.
The PGA Tour needs to implement the same standard imo.