The idea behind these dog whistles is that multinational corporations and rich investors are actually a front for global communism. Yes, ruthlessly profit-seeking investors like George Soros, the man who broke the Bank of England's ERM peg[1], were actually "cultural Marxists" the whole time! Somehow. Ignore them being the worst examples of capitalism, an economic system Marx thought was evil that would eat itself. They said they like racial diversity and feminism, so they're clearly "cultural Marxists".
Anyone who remembers their WWII history should have alarms blaring in their head, because "cultural Bolshevism" was one of noted meth enthusiast Adolf Hitler's favorite phrases, and he used it in exactly the same sense I described in the previous paragraph. You see, it turns out this is actually just about demonizing the Jews, because it is always about demonizing the Jews. They may not know that they were going down that path, but that is where the logic leads.
"Globalism", outside of the dog whistle context, just means free trade and open borders; i.e. standard liberal[2] free market stuff. The people who lost out on free trade adopted the term to refer to the dog whistles I listed out above.
[0] I'm not even going to glorify it with the words "conspiracy theory". A conspiracy theory is a guess on what the rich and powerful are doing that may be right or wrong.
[1] European Rate Mechanism; it was the on-ramp to the Eurozone before the Euro was a thing. The failure to establish an ERM peg basically doomed the UK to never join the Euro.
[2] And right-libertarian.
Many conservative oppose globalism, in particular nationalist and social conservatives. Especially now that, in both the UK and the US, Wall Street/Canary Wharf has aligned itself with socially liberal/economically neoliberal pro-immigration parties.
Obviously the free market types (both conservative and liberal) want to deflect any criticism of these trends. And unfortunately, any criticism of Wall Street/Canary Wharf will draw out some anti-semites. Which is why it's been Labour that's had the problem with anti-semitism: https://www.reuters.com/article/uk-britain-politics-labour-a....
But it’s frankly gross to use that to shield globalization as an economic and political trend from criticism.