You are incorrect, Bush gained five points among Ohio Catholics from 2000 and won the Catholic vote decisively. Most striking is how he did among weekly massgoers there.
Here's some information from the Ohio 2004 exit poll upon which to ground your opinion:
VOTE BY RELIGION BUSH KERRY
Protestant (57%) 56% 44%
Catholic (26%) 55% 44%
Jewish (1%) * n/a *
Other (6%) 26% 72%
None (10%) 29% 69%
VOTE BY RELIGION AND ATTENDANCE BUSH KERRY
Protestant/Weekly (16%) 69% 31%
Prot./Less Often (16%) 48% 52%
Catholic/Weekly (11%) 65% 35%
Catholic/Less Often (13%) 47% 52%
All Others (38%) 43% 56%
Source: CNN.COM
Thanks for the numbers. It is also interesting that the Democrats seem to openly admit that it was midwestern white Catholics that made the difference. Somewhere around here there is a Carville memo with lots of interesting stuff.
I am not sure where your five point swing came from, but in any event that would not be quite enough to swing Ohio. But it is very close to effecting the swing. Without the swing you posit, we would have had a Florida redux.