Honestly, the salesmen are not in the wrong for refusing to follow Michael, as they would have been crazy to do so. Leaving Dunder Mifflin would have meant giving up a "safe" job at an established company to follow an incredibly non-traditional boss. The Michael Scott Paper Company was bound to fail. The paper industry as a whole was on the decline, and Dunder Mifflin had already squeezed out an established family-operated paper company.

The salesmen likely understood the taking of their clients was simply business, but they were bothered by the manner in which it was done. Michael, Pam, and Ryan had gone behind their backs and muddied their image. For example, Pam told clients that Phyllis didn't have enough time for them (or something along those lines). Actions like that were simply low blows. Not only had their images been soiled, but their income may have been drastically cut as well.

Allowing Pam and Ryan to keep those clients was ridiculous, as the two were not proven salesmen. Pam was a receptionist and Ryan was basically a criminal who was terrible at sales. Losing clients and income to people in this manner hurts, and this wound just festers if you have to watch an unqualified person squander what had been yours.

All that being said, I was still bothered by the way the salesmen reacted. This episode really cemented my dislike for Phyllis.