The fear is that if all who are called by God to be priests can be ordained, a priest will be respected and admired and promoted based on his or her talents and spiritual strengths in Christ instead of his grand sacrifice to give up marriage for the sake of pastoring a parish.

Now how great a pastor, preacher, leader, teacher, confessor, etc will be what a priest is valued for and those priests weak in these talents and spiritual skills will start to appear as the weak priests that they are and get pushed aside.  

Also women priests mean women bishops, cardinals and popes, real equality, so no one group of automatically lesser humans - to tell yourself - Well, at least I will always be more important than those people.  This could equally apply if we were to decide we don't need any black male priests or Hispanic priests.   If Trump were pope, people like Pope Francis would be told they can't be priests because Hispanic men are all unclean, violent criminals.