First, this may be the Church's only chance to minister to these children before they go off into the world.
Second, the pastor can always influence the children to get their parents back into the pew, e.g., "Daddy, Father Martin says that if you love Jesus, then you will come see him on Sundays. Why don't you like to visit Jesus, Daddy?"
Third, the pastor may be burning the only bridge than might lead a lapsed Catholic back to the Church.
While I certainly understand the Pastor's frustrations, and do not in any way excuse the conduct of the Parents, I truly believe that the Pastor is being shortlisted in his actions.
I have to say I disagree. If it has to be explained to the child as to why he is no longer welcomed as CCD, their parents are going to have to admit their own hypocrisy. I know it stinks, but honestly, with the decline in attendance these days, vast measures have to be taken. Children are not going to go to church as adults if they were not brought up to do so. I'd rather someone just not bother with the Sacraments at all then only showing up for a Baptism, Confirmation, a wedding and a Funeral and then complain about how much time, effort and money that all takes from them. I attend and put in money EVERY week because I am obligated to, plus the cost of a donation for the Baptism of my kids etc. It just doesn't seem morally right and seems rather hypocritical for non church go-ers to act like the Sacraments are oh so important when they can't be bother with the church for the rest of the year, decade, etc.