You're forgetting that Chock/Bates lost a lot of training time this season because Maddy had suffered a concussion, and they had to sit out Skate America, and then lost their US title to H/D. So it was not that surprising that C/B had some mistakes in their FD and weren't quite as effective as they had been the previous season when they won silver behind P/C in the GPF.
No doubt their mistakes in the worlds FD were a result of so much missed ice time. It isn't a matter of the US 'backing' one team over the other, but the team's performance on the ice. Maybe Canada politics for their #1 team, but then their #1 is clear, which isn't the case in the US. Politicking always seemed like backroom dealing to me.
If Worlds 2020 hadn't been cancelled, I think C/B would easily have passed H/D for a medal, because H/D's programs last season were bad. That's why H/D had a new FD this season and reworked the RD.
Chock / Bates were third on the Seasons Best scores for 2019-20, and 5th in 2018-2019. G/P just won their first world medal, while C/B have won two: silver in 2015 and bronze in 2016. They have won 4 Continents gold twice, in 2019 and 2020; and also won silver in 2015 and 2016 and bronze in 2013 and 2017. G/P have never been 4CC champions, and have two silvers, in 2020 and 2014 (when C/B didn't go) and a bronze in 2019. C/B have made it to 5 GPFs and won silver in 3 of them; they have amassed 12 GP medals, including 3 gold, 7 silver and 2 bronze. G/P have made it to 2 GPFs, but won no medals. G/P have 10 GP medals: 1 gold, 4 silvers and 5 bronze.
So I'd say Chock / Bates have done quite well for themselves despite having such "poor skating skills".