Just not true. Though you can cite a few isolated examples of good teams that have high winning percentages on a home court that they don't practice regularly on, there are many more examples of teams that have far better "home court advantage" on their campus-based home courts.
Here is a list of best home records though 2009- if you correct for the quality of the team (in other words, the best teams will always have good home court records regardless where they play) it is obvious that the overwhelming number of teams ranked highly play on a campus arena where they practice regularly.
http://www.rpiratings.com/homecourtrec.html
Interesting that some of the schools you listed as examples of teams that play in a Civic Arena are ranked surprisingly low on this list-
Georgetown- is ranked only #92!
Villanova is only #68!
Marquette is #57
Creighton (#18 ) is the only one of your examples that is ranked high, but the Qwest Arena has only been open for 6 seasons- which may not be enough time to really compare reliably.
Here is even more proof that you are wrong-
There are a few schools that play some of their games at a Civic Arena, and also some at a campus arena. If this "practice" factor didn't matter, these schools should have similar records at both sites, right?
UConn's record at the Hartford Civic Center is .7532- ranked #77, but their record at their campus arena, Gampel Arena, is far better at .8557 (that would rank 12th if it was listed).
Seton Hall plays some games at the Meadowlands Arena- their home court record there is .6716 (#185). But their record at their campus arena, Walsh Arena, is far better at .7342 (which would rank #99 if also listed)
St. John's home record at Madison Square Garden is a lousy .6100 (which would be #259 on the list), but their record at their campus arena, Carnesecca Arena, is an amazing .8267, and that is the #26 best record among D1 schools!
St. Joseph's record at their campus arena- .7852 (#46) but at the Palestra .6803. (would rank #177).
South Alabama's record in their new Mitchell Center is .7248, while their record at the Birmingham Civic Center is just .6938, but their record at their previous home gym was .9286!
In every case where schools play some home games in a Civic Arena, and some on campus where they practice,
every school has a better record on their own campus arena, compared with the Civic Arena where they do not practice regularly.
And here are some other schools that play all their games in a Civic Arena-
University of Southern California plays at the LA Sports Arena, where they have acknowleged for many years that they do not have much of a "home court advantage". Despite having decent teams, their home court record there is only .6599, which ranks only #206 on the list- one of the lowest rankings for a major school.
University of Wisconsin-Milwaukee plays at US Cellular Arena- their record there is a lousy .6412- ranked #230
Long Beach State plays at The Pyramid in downtown Long Beach. their home record there is poor- .6382, only #234 among D1 schools.
And I could continue and list more, but it is obvious that the home court advantage for a team that plays on campus where it practices regularly, is a significant advantage over playing home games in an arena where they do not practice.