Not a supporter, but he didn't "flee" to UK, he went here after having been told he could leave Sweden as there were no obligations for him to remain after the initial investigation into the rape (Sweden's legal interpretation of the term) allegations. Whilst in UK he was under effective house arrest. Then, a grand jury was convened in US, while the Swedish prosecutor decided (on her own and aided by false testimony) that more questions needed to be answered, but rather than travel to UK (as had been done for suspected murderers) issued a EAW instead. This then gave "legitimacy" to UK police to arrest him. He then sought asylum in the Ecuadorian embassy, where he has been for over four years. During that time, there have been repeated requests for the Swedish prosecutor to question him in the embassy as a guest of the Ecuadorians. She refused every single one and never gave a reason why, something that got her censured by her own people for basically fucking around over what, on the face of it, was a simple and straightforward case.
If you had been accused of a crime, released without charge and assured that you were free to leave the country, and then a continent-wide warrant is issued with every possible legal avenue taken to question you again (plus an illegal one, a threat to storm an embassy. That last happened in UK to Iran's, where they had hostages) except the *easiest*, wouldn't you think there is possibly some hidden agenda?