That first study you linked about the Medieval Warm Period was written by just one guy (wonder why he couldn’t get anyone else to co-sign his paper) and they’re basically climate change deniers, not “we shouldn’t be alarmists”-ers.

The work I linked is not a study. It cited many studies on the Medieval Warm Period.

I think you are basing him being a denier on what he said in 2013, it's about the haitus and he's acknowledged warming in the 1900s. (“Global warming ended in 1998. […] There has been no global warming in 15 years.”). This was said at the end of the 15-year hiatus (1998-2014). The hiatus was even acknowledged by the IPCC in its 2013 report.

And here's Chinese climate scientists acknowledging a decrease in temperatures in North America during that time period in a peer-reviewed journal. So there was some substance to what he was saying at the time. https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018EA000443

In North America, the minimum temperature experienced an obvious decline during 1998–2014

Edit: I'll respond to the first part too in a later reply.