And Brexit, and French and German elections, and shoot down Dutch airlines, etc.

You see, when anything go wrong in the world it's Russia's fault:) Especially if someone loses some elections - blame Russia 100% of the time.

Except... those things explicitly are Russia's fault. You can keep pretending Russia is a benevolent member of the international community all you want, but that simply does not make it true.

I’ve previously heard that claim about Brexit, but not about the other three.

Even then, despite being so Remain-y I moved to Berlin, I don’t see how Russia made enough of a difference to count as successfully interfering compared to all the decisions taken by Cameron up to the day of the referendum itself.

Well, the US is since WWII meddling with elections in other countries. And not only that but actively toppling foreign governments. The few millions some Russians may have spent on ads are a drop in the sea compared to the billions and billions that PACs and SuperPACs have spent.