Those supporting the shorties are still stuck at the end of 2020 mindset , at that time,( which also coincide with JPM publication) assumptions were

1) recovery is coming fast in 2021 (no longer valid now, just look at the trend of the banking counters which is the best proxy to recovery theme)
2) vaccine will be the miracle cure (no longer valid now, less effective than expected and problems in implementation)
3) covid spread will be contained just like that (no longer valid now as more variants of the new strain of covid keep mutating--just look at the no. of increasing cases in Malaysia in Jan 2021 )

Assumptions made at end of last year is as good as they are at that time, does not mean that they will be absolutely right going into 2021. Things can change and events can take an unexpected twist going into the future

Adjust your gameplan accordingly. Just my 2 cents