They believe that it's 'Jesus only', therefore, when they see all the 'tradition' being practiced they assume that all those things are 'needed' as well.
I'm glad we can dialogue about it. As a Catholic, I like the tradition. I do believe that the Roman Catholic church honors the good traditions (and some are important to our worship as well) as a way of helping us humans who may approach Mass and worship with burdens that might hinder our participation. On a simpler level, just as the sight of a birthday cake and gifts might help us shift gears and celebrate with a loved one, so, too, do traditions help us shift focus from self concerns to Heavenly ones. Just the same as families and cultures and communitites have traditions that unify them and remind them of why they are doing what they are doing and why it's important. I know that in their own unique way, many Prostestant churches have their own traditions, even if they aren't woven into worship, that help their communities.