Nothing to do with Godwin as the salute has nothing to do with Hitler.
(The West of) Scotland has a long standing divide along religious (or rather sectarian) lines. The manifestation of this that people (in England) recognise is at Rangers/Celtic games but also extends to what pub you drink in, sometimes what area you live in, what party you vote for and certainly which side of the Yes/No you were on.
Three out of the four areas which voted yes have strong Irish/Catholic connections and populations. This imo isn't a coincidence. I saw many Irish tricolours at Yes rallies as they tried (unnecessarily and inflammatorily (this is Glasgow ffs)) to claim solidarity with the plight of the Irish. The No lot, the NI loyalists, unionists and Rangers fans counter with the Union flag, Red Hand of Ulster salutes and Rule Britannia.
The carry on in George Sq had f all to do with Britain First, it was a response to the attempt and subsequent failure of the Yes lot to break the history and traditions that many hold dear. Salmond criminalised the singing of many traditional Rangers songs, many have been jailed so this was a big GIRFUY moment for them.
This song is now illegal to sing in Scotland. But these people haven't disappeared.
https://www.youtube.com/watch?v=ZyVEV9Exuho
I'm a unionist and Rangers fan. Do I agree with brawling in the street? No. Rightly or wrongly do I understand the outpouring after the sustained attack on the country we believe in? Yes. I watched the whole referendum night on the BBC. Was there any mention of religious belief re the vote? Nope. Was it a factor? In Glasgow it's always a factor.
One thing's for sure, if Yes won it would have been a lot worse.