They are, suggesting they aren't is just sophistry masking as clever insight. Any similarities between the two are superficial rhetorical details - comparing them with respect to their careers as elected politicians demonstrates an obviously massive chasm between them.

Do you feel they agree on many topics?

Your location on the graph is a measure of the cohesiveness of your overall policy preferences, not necessarily the zealousness or character of the person who holds the position.

Technically Trump is anti-gun and Sanders is pro-gun. That's enough to pull them closer towards each other on a graph even though they are diametrically opposed.