The charges were "timed out" rather than "dropped by the Swedish courts", though the latter may well have been the last word in the matter.
In other words, prosecutors had only a definite period during which they could possibly bring charges and they failed to do so. This "elapsed time" system applies in more than one country in the world.
I don't agree with it. A crime is a crime and an accusation thereof should be properly and judicially dealt with...in the form of a case-hearing not a rubber-stamping dismissal exercise.
"What is it to me?" Only the desire to see justice done, whatever it turns out to be, whether that would have been "Guilty as charged" or "You're free to go" for Assange in Sweden.
Sadly, he scuttled away - just as he tried to do in Britain when he had broken our law. He will doubtless go on trying to do the same as regards the charges the USA would like to put to the test, if they get him.
I wish them luck!