The "Kent variant" (later "English", now "Alpha") was first described in Sept 2020, widely publicised as having become the dominant strain in the UK in late Nov 2020.

So a geographic label was widely used before Biden without apparently causing ructions. It was adopted because the released name for the variant, lineage B.1.1.7, was less convenient or distinctively memorable for the public. If it had been repeatedly referred to as the "Kentish virus" by senior politicians then a similarly hostile reaction might have been seen as was for "Chinese virus".