The real issue here isn't whether Mint Press are as dodgy as fuck or whether Greyzone is or whether the Mason map of left groups is accurate or inaccurate is it? Nor is it do posters like/hate/ really don't know about so and so's view on the Russian invasion. We are all old and wise enough to form a view, reject/oppose a view, work around these things etc. Normally we'd do this in discussion or debate or in some cases avoidance and boycott. Throughout my working life I've had disagreements with other activists and union members on issues like Russia, China, Ireland, reform /revolution, and stacks of things but always, mainly out of necessity tbh, worked with good militants on things we agree on and were worth fighting for.
The issue with Mason is that what we have is a proposal from him about a campaign to out and target what he and obviously some others see as pro-Russian and pro Chinese sources using government guidance around disinformation. It was positioned as a 'peoples' type campaign, trade unionists, the church , NGO/charity- a popular front against 'disinformation' ironically modeled on what used to be bog standard Communist Party tactics. A campaign that squares with his position that the left should support the EU and USA powers against Russia and China. That in itself might raise an eyebrow and also about its limits ie how far and to whom should the 'cleansing of the left' or the 'de-communisation of communists' go? This is very different from the methods mentioned in my first paragraph.
However, if those emails are true, and that is a big if , he has moved up a step and a half. The reality is that those emails suggest he is not just proposing but has already made contact and plans to collaborate with a whole number of people a stone's throw away from intelligence assets and closeness to security services., and not just on a national scale but internationally. As one of the emails advised ' contacts in the government but not controlled by the government', in other words state sponsored.