Part of the reason ties into centralization. If Twitter was plumbing, i.e it formed the backbone of apps (which it does not, as their API is forever shifting and not 'open' in the truest sense), then sites like this could be tolerated. It would be perfectly okay to have an ecosystem of non-siloed data which originally resided on Twitter's servers, but Twitter exercise ownership for that data, and are using sites like this to make an example of people. A bit sad really