If I recall correctly, the only problem the Rosh had with saying words along with the Chazzen is that you might say Hashem’s name, too.
When I am by the Amud I appriciate the humming along, as it gives a positive feedback that all is going well.
However, I think Krias Hatorah is worse. Ignoring the Baal Koreh is like ignoring the voice from sinai. So sayeth the Sefarim.