Is this in reference to me? On a forum it's impossible to hold up 'credentials', though I assure you I have them - both research and teaching ones. I also spent a lot of time learning a lot of nonsense when I was at university, since I was unlucky enough to be there when monetarist thought was extremely dominant. It has taken me a long time to undo the damage, but I worked for it. I emptied my glass and started again because the facts didn't fit. Other people got their first and I'm happy about that. Plenty of us who knew monetarist claptrap wasn't right and worked to try and undo it with coherent theory have been blessed that the internet allowed people to share research that led to this.
I was sceptical about some points, but I didn't puff out my chest and say "what makes you right?!' I went and read from the source I put aside what I knew and paid attention. Since MMT/post-Keynesian economics has become a buzzword in the last two years or so people tend to think it is some new fly-by-night thing, but it is the result of decades of work. Which has antecedent theory stretching back over 100+ years. Several key understandings have locked a lot of things into place. Some is just rediscovery.
That's fine, but MMT is completely in line with Keynes's observations (Keynes was a good student of Marx's work and so adopted the theory of effective demand from him, it's a forward momentum). When you say "just an good old fashioned Keynesian", it really should refer to what Keyenes says, not how his position was reinterpreted through the 50s to 70s as a synthesis of a bit of him and neo-classical economics. That's what people are usually referring to when they say "Keynesianism". Anyone in agreement with Keynes can't fail to find MMT both compelling and shockingly coherent in its clarity. Over the years it has made me go back and actually read Keynes more thoroughly.
On the point of "act like PF is full of fans of neoliberalism", the issue is this: it is often unwittingly being in line with monetarist cant (since it is so embedded in public discourse by now) and then when this is pointed out/explained, the person gets annoyed and digs their heels in further. Against their own best interest so often. Causes frustration. Also me being painted out as some crazed 'far left' person when discussing the functioning of monetary (capitalist) economies. It can be trying.
I don't find people here to be 'idiots'. No-one likes to be told they are in error, or to feel that what they thought for so long just evaporates under force of logic and matters of fact. I felt that about economics I had understood for a long time. It takes some courage and humility to be corrected and to learn new things.