When the current government first talked about UN "peacekeeping" (really joining a small war) quite a few people with experience in such things explained why this wasn't a good idea- casualties, cost, futility, incompetent UN command etc. It appears that Trudeau listened. Now many of the people who were against "peacekeeping" realize that without it there will be little for the army to do- less cash, adventure, medals, senor jobs in UN HQs etc. and are complaining about the lack of a decision- really a decision they like. Staying out of small wars or peacekeeping in Africa is wise.  

This has nothing to do with party. Harper changed his mind on the utility of force in Afghanistan. Both Trudeau and Harper appear to have been sobered on using the CF by proximity to the practical problems of  ground deployments. in particular.