I'm not blaming them for actively opposing them, but for being incompetent about it. Given how close both Brexit and Trump were marginally different approaches could sway the needle back into sanity. In the case of Trump this could be just that deplorables moment that cost Hillary the election. It wouldn't be a landslide victory, but she might be able to eek out enough to win if she could control herself. If not that plus a few minor differences would work for sure - her weird behavior certainly cost her votes too.
With Brexit I don't know about any such single moment that I would realistically expect to sway the electorate the other side, but the Bremain side certainly didn't make enough effort to reach the deplorable vote. They would have to dumb down the message at times in order to pry away voters from the clearly horrible choice. When it became clear they weren't listening to the experts it was high time to dumb the message down at times in order to either secure a portion of the deplorable vote or at least discourage them from voting for Brexit.
The opposition in both cases deserves criticism for not doing their job well enough. Both instances are where the deplorable vote gave victory from the jaws of defeat to the clearly horrible option. We need to learn from these mistakes in order not to repeat them - in Germany, France and the Netherlands, possibly also Italy in the next year alone. Filon leads LePen by two votes to one in polls, which is probably more than the deplorable vote can compensate for, but Italy, Germany and the Netherlands are a different matter, where the deplorable vote could potentially become an indispensable part of a ruling coalition. This is essentially a victory for them, even if they have only 10-15% of the vote. They need to be tackled, and the sane part of the politics is the only thing that can - and it can't do it by not trying, that's for sure.
McHrozni