As I have said before, I was a charismatic/pentecostal the first 15 years after I got saved. I was lied to in the Vineyard, the Pentecostal church had no time to counsel a couple with marriage issues (10 pastors, 1 couple!) (but we got help later from secular sources!)
The other BIG reason, is that I began to see the shallowness of the doctrine. Everything was about tongues and signs. Although I will admit that some of the Pentecostals did have a heart for the lost.
I also saw that shallow doctrine resulted in shallow and unethical character. Nothing that was preached, was what I was reading in my Bible, which I loved to read and study.
So a few years in an Evangelical Free church, which had an elder board that was dominating and controlling, and kept firing awesome pastors, if they didn't tow their line.
Finally, God called me to a Baptist church. WOW! I finally heard a preacher who was preaching from the same Bible I was reading. His knowledge of the Word of God was amazing. And when he started encouraging the young men to go to Seminary, I heard the call of God - one of the best things that ever happened to me - growing and getting close to God, hearing his voice, and really learning the Word of God.
I am in my third Baptist Convention, after moving a few times. I love my church. People raise their hands, as the Bible says to do, in praise of God. The messages are incredible, with real unity from week to week, even though we have a different preacher every week in the summer. It is God orchestrating the message. That is the Holy Spirit moving!
And the depth of character in the leadership - pastors and elders is astounding. From small things to the big - I see people who are truly deep in their walk with God and teaching it in word and deed to the congregation.
So my answer is that all these nonsense demonstrations are actually destroying the walks of Christians. Instead of digging into God's Word for answers about how to live, they get caught in the very shallow experiences and outer signs, instead of growing in both in spirit and in the knowledge of God's gift to us - the Bible.