Yes and no.
Do i think there's a good list of times he's crossed a line with things like this - yes. Not entirely sure what the caption was meant to mean, being charitable i'd suggest it was an attempt at dark humour or some kind of 'religion controlling the masses' statement, but it's obvs completely off, anti-semetic, and not at all cool.
Do i think that is clear evidence he's a neo-nazi white supremacist - no, not at all.
Problematic behavior and/or selected bad takes from decades of online presence is, for me, not this cut-and-dry evidence of someone's political views, especially something so extreme.
He has a record of supporting good causes that are antithetical to right wing politics, be that via tattoo benefits, doing flyers for punk benefit shows, or even the donuts in support of BLM that kicked this whole thing off.
I know you can posit that these are all acts 'performative wokeness' (and online other have done so) - but having a number friends and acquaintances that have know him for years and years and can only report his politics as being on the left - I just think the chances of him having secretly harboured such horrible views are slim to none.
And I can't stress enough that folks close to him I've chatted with since are similarly gobsmacked that the accusations have been made against him - and acted on in a fairly major way (doxxing, business vandalised). It's not that I/they don't see where the people that are angry are coming from RE: the optics, I'd say their hearts are in absolutely the right place - but that the conclusions drawn about Simon are just not true.
I'm also aware that 'plausible deniability' is a thing - but for me, selected bad takes and questionable imagery (as others have said - it's not like he's hidden his affinity for this stuff) do not automatically a neo-nazi make, at all, whatsoever. Folks can disagree with that, and about the validity of using symbols the nazi's used - but ultimately if you don't know the dude personally, it's all assumptions being extrapolated upon.
I mentioned in the vegan thread that theoretically if you didn't know me, someone could piece together old photos of me with a Burzum tattoo (granted, now covered), questionable band shirts, and shitty jokes made on facebook 10 years ago - and make similar absolutist accusations, which is a bit terrifying as a lifelong lefty.
Really hope this doesn't all come across as hand-wringing, or dismissive of the wider issues of racism/shitty politics. Especially, as @ltc mentioned, this stuff seems to be completely over-shadowing the more important issue of a member of staff having been racially abused by another a couple of years back - and figuring out what went wrong then that it wasn't properly addressed, and how to make amends to whatever extent is possible at this point in time.