I disagree with this completely. If you are called to be a Catholic Priest and are involved with a pro-life cause etc. that should be encouraged. This is such an important issue that really every priest should be involved in it.Distractions are not just girls but also potentially some of the same things that drew you to religious life to begin with. But being overly involved with something outside your formation and outside the community being built can be a problem - even if it is pro-life cause, or saving the environment, or what-have-you.
Also, I don’t see how going out to dinner in and of itself would be an impossibility for someone in formation. I know that friends are allowed to visit our novitiate and I don’t see it as a particularly bad thing for a group of friends to go out to dinner. Especially if part of a prayer group or something.