It's probably because President Obama and Angela Merkel don't/didn't generally do things we associate with regimes. President Obama on numerous occasions at the start of his first term attempted to work cross party. I think it's generally used more when talking about a dictatorial style of government. President Trump, regardless of whether you like him or not, is not a consensus builder. His style is that of directions from the top, no compromises, everyone is either with him or they are potential enemies. I think this is why you would see it used more. I don't know that it demoted a bad or good government more than any other word, nor would I read into it that way. It's quite possible that it was intended to be read exactly the way you're describing.