The left and liberal media's biggest mistake was not crediting Trump for doing the good that he did. He did implement policies that helped the economy, and did good work keeping peace in the middle east. For sure, in his 4 years he did some good... The bad he did wasn't purely policy based. He made bad policies, he didn't keep plenty of promises and he lied his ass off.
The cultural shift he created allowed your country to be divided completely. He made politics about good vs. evil , so that his opponents were becoming to some, satanic baby eating murderers. When a country is as divided as it is now directly after a controversial president is voted out would lead some to believe that a lot of the division that exists now comes directly from him. That's pretty easy to see as an outsider.