Racist is not the word you are looking for to describe how they act towards other species. The proper term is Xenophobia which is the fear of other species/different creatures.
And I don't see any pony who acted all strange to Gilda except for Pinkie who has never seen a Griffin before. Everypony else didn't seem to care unless you saw something I didn't. Notice nopony cared when the Griffin chef arrived on the train.
The only other species I can think of is the Buffalo's but that was about listening to one another's problems against 2 stubborn groups. No Xenophobia there, just a huge misunderstanding.
Cows seem alright and get along with ponies as do Donkeys. Zebras are now more accepted once ponies got used to Zecura.
The only species they are 100% afraid of are those that have tried to hurt them: Windigos, Timber Wolves, and Changlings.