The rabbi of a certain synagogue in my town entertains gentiles for Torah discussion. He allows men and women to discuss Torah in same class and he allows gentiles to join the congregation in prayer. On two occasions there were two gentiles who attended services wearing techeles tzitzits. This felt very terrifying to me.
I no longer am part of the synagogue.
Is this permitted or did I encounter differences in Torah practice among different families of Jewish faith?
The way you are describing it, something doesn’t sound right, but I can’t say anything without hearing the other side. If you don’t like what you see there you may daven somewhere else.