Rar left radicals here

I take it that means "far left" rather than "rare left".

It's worth pointing out that, by US standards, all significant parties in the United Kingdomm (and most of the less significant ones) would count as "far left".

And I don't think anyone could seriously suggest that scandals about policians private lives are more (or less) frequent on the left right or centre of politics anywhere.

The real damage to the parties isn't so much the shock caused as the derision that it gives rise to. Which tends to spill over into derision directed at politicians generally, because any affair like this immediately revives memories of the ones involving leading politicans from other parties (and the papers make a point of reminding people in case they have forgotten).