Ever heard of a rally-killing home run?

I ran into this earlier today:

Even coach Ray Tanner has hesitated to embrace the long ball. After USC beat Clemson on Wednesday night with four solo homers, Tanner said all the solo shots worried him because he was always taught they were "rally killers."

The full quotation, from another article:

Again, though, each of their homers came with nobody on base -- a fact that Tanner was as quick to point out.

"When you hit solo home runs, it starts to worry you a little bit," he said. "I've always been told that solo blasts are rally killers."

Ladies and gentlemen, Ray Tanner, the only manager in America who gets worried when his team scores. Who imparted to you that nugget of wisdom, Ray? Dusty Baker?

A solo home run (a) nets the team a run and (b) does not result in an out. This harms what, exactly? Is he really saying that hitting a solo shot decreases the likelihood that a team scores multiple runs in an inning?

Tanner is a great coach, but that's crazy talk.