Is this based on basic research or demographic analysis? Has the research ruled out the possibility that people who are being treated for high blood pressure are more likely to be older and in poorer shape? Because that's a pretty strong confounding effect unless the research in question is a randomized controlled trial.
I've also heard conflicting reports about Ibuprofen. I don't think anyone knows for sure.
My initial thought on Ibuprofen is just correlation not causation. How many people who get a fever will try Ibuprofen to try to lower the fever? Probably quite a few. When these people die its easy to say "well they all had Ibuprofen". That doesn't mean it had any effect.
On the flip side, NSAIDs do reduce inflammation and inflammation is part of the body's response to various stressors; I could see that lowering our response leads to worse outcomes when sick. I have always thought that cold medication increases the duration of a cold just from my own observations, so I do find it at least plausible.
I agree on the high blood pressure, if you are on it that means you have hypertension and are likely in poorer shape than someone who does not take it. I can somewhat see diuretics having an impact though as those can flush needed minerals out of your body when your body is in need. They also dehydrate you, so if you are on one and don't get properly hydrated and have a proper mineral balance, I can see that being a big negative.
Speculation surrounds ACE inhibitors (ACEI), which are a type of high blood pressure medication, in that they may dampen your immune response to viruses over long time usage. The other speculation is that circulating amounts of ACE2 are increased by ACEI and SARS-Cov-2 specifically binds to ACE2. The confounding aspects are as you suggest that the overall health including kidney health are often poorer in people with hypertension.
I've also heard conflicting reports about Ibuprofen. I don't think anyone knows for sure.