Well, if it would be taught, as it was taught in the bible that speaking in tongues is one gift like all the others, I would agree with you.
But since 1900 it is taught that speaking in tongues is the evidence for to be baptised with the Holy Spirit. According what pentecotals/charismatics teach about speaking in tongues it means that not all Christians can be baptised with the Holy Spirit, because Paul taught that not all getting the gift of speaking in tongues.
The doctrine we found since 1900 we find not taught in the bible. You can claime that acts 2,8, 10 and 19 is a evidence that it was taught, but this events nowhere are quotet in the letters to the New churches as an example for an baptism with the Holy Spirit f.e. as for empowerment. So someone also can claim that acts 2,8, 10 and 19 are written down for to show the jews that the Gospel is for all mankind equal and not for them alone.
Not the Theology behind is the reason,that people turn to Christ. It is the word of God and God himself who addes the people into the Body of Christ.
And Yes, pentecostals and charismatics spread the word of God, but this is no guarantee for to be right in all teachings.
And the other thing is, that we dont know the hearts of people, but God does. And God is not seeing our theology, but our hearts.