The idea of having the Windigos return was good. The implementation was pretty shoehorned, though, yes.
To be fair, they didn’t just spread rumors - they also fabricated evidence. Unfortunately, that wasn’t shown in the finale, merely explained as they went. They like, stole food and committed arson and stuff like that.
I accepted at face value that racism was easy to spread in Canterlot, which has been shown to be full of rather pompous and bigoted people and was the direct city targeted. Buuuut it was a bit odd that everywhere else in the nation followed suit within what seemed to be a very short time span.
And yes, if Chrysalis repeatedly came out of bushes to slander random people, I don’t see how that was so successful over the long-term lol
Something that is repeated in MLP FiM is that the ponies are not good at social communication, so they constantly misunderstand one another, come to hasty conclusions and tend to talk past one another or simply not talk about each other on topics they need to vent. This is much of the basis for the focus on friendship in FiM, as the ponies are very emotional creatures that could be very self-centered and not adept at socializing in depth. This is intended for entertainment for growing children who needed to learn how to socialize with each other as they slip into the community, “friendship lessons” and focus on friendship - which has formed the basis of popularity for viewers of the TV show.
The ponies are just too intense in the emotional field.
Besides, Tirek had said it took him several weeks to figure out how to use the bell - and Discord simply didn’t have the Legion of Doom under surveillance. They probably had at least a couple of months or more to undermine social stability, and they didn’t have to cover all of Equestria. For Canterlot, Ponyville and Cloudsdale, the central country is at an appropriate distance from the larger population centers of Equestria. That’s why the windigos had come to Canterlot, Chrysalis had been able to concentrate the distrust of the ponies without diluting it to the rest of Equestria.
Also, there are very serious limitations for the producers in their work on the TV episodes in just 22 minutes at a time when the focus had to be directed to the action event.