They call the themselves nationalist, the party was born out of old nazi parties and many of their prominent members express deeply racists in miscellaneous web forum. I think this is more than enough evidence to call them far right. Just because you don’t agree with reality it doesn’t mean that it is biased.

Regardless of whether or not you support Sverigedemokraterna, they are widely considered to be right-wing or far-right [1]. Politico is not taking any stance or making any kind of statement by labelling them as such.

[1] https://en.wikipedia.org/wiki/Sweden_Democrats