The parent poster doesn't realize the inherent bias in what they wrote and that you have pointed out.

I believe their point is that, because the US is generally regarded as 'to the right of' many countries in Europe, for example, a slight rightwing bias looks to us (I'm in the UK) like an extreme rightwing bias. Heck, even a completely neutral stance, as far as the US is concerned, will look like it veers to the right for us. Note that I'm not saying anything about how I believe the twitter algorithm should work, this is just my interpretation of what that commenter meant.