There is a chance this will derail the intent of the thread, but I'll continue to defend Welsh on that...to an extent at least.
If the Reds are losing 4-1 in the bottom of the 9th and there are two outs and a man on 1st, I would rather the batter in that situation draw a walk or hit a single than hit a HR.
I truly believe a pitcher would be more likely to tighten up with runners on than if the bases had been cleared.
My reasoning
1) Human nature. Something "cleansing" about a clean slate on the bash paths
2) Ego. Pitchers like their numbers. If a pitcher gives up a two run HR, I think he might actually loosen up a bit, knowing he's already had a poor statistical outing. Now he knows he just needs to get this batter out and end it.
3) I'm not sure on this, but I'd guess there is a higher statistical probability of a walk/HR combo than a HR/HR combo.
In the end, I don't truly believe that a HR before the game is tied or won, "kills" a rally...but I do think there is some credence to what Welsh is getting at there, I really do.