"Will someone please sue these fuckers!"
In the UK there is something called the Small Claims Court which is designed for, well, small claims. It costs very little to get into and involves magistrates (IIRC). The fees are here https://www.gov.uk/make-court-.... Lawyers are generally frowned upon as I recall because it is a form of arbitration between reasonable people.
It might not sound very exciting but you claim for your costs for reinstating your system after it was broken. So if you do it yourself, you might price your time at say £20 per hour (reasonable) or you might hire outside help at say £30ph. It will take say five hours to find and copy all your data off to a USB disc that you had to buy at say £80 plus the two hours trip to town. Then you have to restore your system from source - let's say you still have a Windows restore partition - that will take a good two hours. Then you have to patch it - another five hours. Reinstall your apps - another five hours.
So 5*20 + 80 + 2*20 + 2*20 + 5*20 + 5*20 = 17*20 + 80 = £420 minimum
That's for someone who knows what they are doing and are being reasonable. For an IT duffer then the £30+ph is more likely because they will need professional help (receipts please).
The whole point of this is that MS (if they really are pushing forced installs) will end up with some form of court judgment against them and you will get recompense. The SCC is not a get rich quick scheme. It is designed as an easy to use and cheap way of reclaiming monies. It has worked very well for me and some friends in the past. In one case the threat of SCC was enough to make a very, very large multi-national do the right thing because of the fact that the SCC is a serious court and a judgement against you can look a bit shit (especially when publicised.)
Now, if after restoring your system it does yet another win 10 breakage then you can always do it all again. If a few 1000 people do this it could be interesting.
I am making a big assumption here which is that you will probably have to persuade the magistrates that your system was broken by MS's automatic "update". You would have to make a formal claim to MS first requesting payment for your time. You would also have to demonstrate that they refused to comply.
Worth a crack though