That's your opinion. Alternate history is mostly ASB. Why do you think alternate history always asks "what if?"
There's a big difference between ASB, which refers to things involving time travel, elements of sci-fi/magic/other fantasy stuff, or is so completely and utterly implausible that it would require that sort of assistance to make work, such as the unmentionable sea mammal, and the stuff more normally discussed in the other forums, which asks what if 'x' instead of 'y' happened at a given time/place.
To properly ask such a question requires a given understanding of that situation, all the variables involved including the people, the assets they had to work with, the way they thought, etc., and from that, one can find out what would need to happen differently to get 'x' instead of 'y,' and whether that change is both possible and plausible within those parameters. Assuming that your proposed change passes those tests, one can then go on to what the results of the change will be in both the short term and long term, extrapolating from the trends involved in OTL, although the farther on that goes, the less useful that becomes because of butterflies, and there is a degree of creative license involved, within reason.
Your scenario has Britain, in throwing a temper-tantrum over American reluctance to intervene militarily against the Bolsheviks, deciding to commit an act of war against the United States, which given the exhaustion of Britain following WW1, its need on American food and money, and the near certainity of ailenating most of the rest of its allies (and probably several of the Dominions- Canada would certainly be appalled) would be an act of reckless insanity of the sort only seen from some of the more colorful dictators, as many of the posters in this thread have tried to point out.
However, given your persistence in this, as well as some of your other threads, continuing the argument does not appear to be a productive use of my time, because, well.....