I think it's mainly a general UK feeling that the EU in all its forms keeps on trying to dictate to us what we should and shouldn't do, and to make the UK more Europe-like. It doesn't help that here the Human Rights Act and the ECHR is treated as yet another avenue for protesters to use, especially when public opinion is against the protester. It's meant to be used for major cases involving widespread violations of human rights (such as the overuse of stop'n'search), not cases like "closing this footpath is a violation of my human rights because I like walking on this path" or "building this new bus route on a disused railway line which lots of people want is a violation of my human rights because I walk my dog there".

The other problem with the ECHR is that it's not actually setting Europe-wide policy. The UK is far from the only country in the EU that doesn't let prisoners vote, and yet there's no mandatory EU directive that prisoners must be allowed to vote. The same thing happens with other significant cases handled by the ECHR - they pass down a verdict, but only the country the case is actually from has to obey it. There'd likely be less fuss from the UK if the decision was actually Europe-wide, but as it is it does feel like we're being singled out.