I used to live in Gladwyne back in the early 2000’s and I am not surprised by this at all. These folks are well insulated from Philly’s crime and violence. In fact, the only non-whites I remember in that neighborhood were pro athletes, pro sports coaches, and the occasional celebrity. I’ll bet over 80% of the parents in Gladwyne send their kids to Haverford (boys) or Baldwin (girls).
Go down the hill a bit into the rest of Lower Merion and things get a little more colorful.
Lower Merion is mostly uber left, except for Bryn Mayr and Bala Cynyd.