The idea that anyone could be able to heal others… undermines the importance of Jesus’ miracles

You mean like in Mark 16:17-18 where it explicitly states this to be the case?

Also, calling someone extremist because they’re a charismatic is a bit of a push.

You being ‘offended’ because his view may push away non-believers because of how ‘out there’ it is doesn’t give a good impression of yourself, everything we believe is ‘out there’ to non-believers, the personal God, prayer, miracles, resurrections are fine but the tongue bit? Oh way too far, may put some people off. Be more concerned with growing in your relationship with Christ than watering down anything that other people may find strange.