conflate liberal/conservative with the dominant left/right parties in these nations
does not include people who do not identify with one of those dominant parties
have some somewhat unreliable stats magic behind them
A lot of young men in the US are reporting themselves as "not a Democrat or Republican", and that's causing a lot of this proportional shift. I would bet that characterizes a lot of folks on this site who are not conservative.
At the same time I know many people (my brother included) that claim to be "independent" because they think that the trump camp is somehow outside the conservative camp, and therefore respond "independent" on polls. Because they think "I'm not democrat or conservative, I just want to drain the swamp" and then support trump, who is literally a swamp.
On the flip side, in Europe extreme right parties are mostly being propped up by young men, while in other age groups men and women vote relatively similarly, which supports this finding.