I'm not sure if its anti-Catholic. Its not Zen meditation. In a Zen meditation, the person tries to empty their mind completly. In centering prayer, the person "centers" their mind around a Christian aspect: whether it be Christ himself, a theme of His ministry, a lesson of Christ, etc.
A big proponent of centering prayer is Father James Martin, SJ. Just do a quick search of "James Martin, SJ, centering prayer" and you can find hits that explain it much better than I do.