Says who? Like, can you point to objective evidence somewhere that indicates it's a bad idea?
@Torc - Adam Schefter also said special teams blunders have played a role in three of the Rams' four losses this season.
I'm WAY too lazy and not being paid to research the results of firing a unit coach in-season. Not sure how you'd even measure that. On a pragmatic level - when you fire a coach during the season you have to be able to replace that coach with someone who is an improvement, and you have no access to other teams' staffs to do so. That means either promoting someone in your organization or finding someone who is currently unemployed to fill the role. In the Rams' case, they're promoting their assistant special teams coach. I guess time will tell.
As far as special teams blunders....sure. The Rams' special teams allowed a 58 yard punt return. I notice the defense allowed a 55 yard run by Kenneth Walker. I bet defensive errors played a role in 4 of 4 of the Rams losses this season. Opposing teams scored over 30 points in 3 of the 4 Rams' losses this season. Again, I'm too lazy to research how many of those points were directly attributable to the special teams, but surely the defense has some culpability too. I mean, if they'd been taught to jump on a loose ball even if they're not sure it's live, we might not be having this discussion.
And I'm not necessarily trying to be objective. I'm being entertained by watching a rival team flail around and saying that it LOOKS LIKE scapegoating to an outside observer (meaning myself).