You couldn't be more wrong. I have the network to prove it, not just speculation like you have.
What do they all have in common? Well 1. they put out spinned content, a lot of it which is junk on their network. 2. The content is all over the place as far as topic/category/keywords. There's your footprints! The new algo came out which specifically targets this type of BS! So guess what, your site takes a hit.
This is not even close to the footprint. BMR had all of their sites on SEO hosting, that's their footprint. Who uses SEO hosting besides networks?
ALN had tokens all over the place connecting all of their blogs to each other, that was their footprint.
I have thousands of indexed links using all sorts of spun content, that's not what Panda targeted.
If your site has thousands of links coming from those shitty deindexed sites, guess what... you get bitch slapped, or worse also deindexed!
Never true, and never has been true. I have used BMR and ALN on at least 40 sites, and not one of them was slapped or deindexed. Sure, there are people that were deindexed after using ALN, but that doesn't mean that ALN was the cause.
The search engines are not that smart! They don't have secret access to secret info, they don't use OCR! They've developed a way to tell grammatically incorrect content/ spun content which doesn't make any sense, versions of which appear all across the web on sites that post way to much unrelated garbage every single day and have deindexed them. End of story!
Google does have and use OCR. They index thousands of old newspapers. Just google "google OCR", they've been using it since 2009, maybe longer.
Google has not deindexed my spun content, but I take time to spin to very high levels, usually above 98%.
If a lot of your links come from deindexed sites, you will be penalized. If flags go off about your site's content and or links, you might have someone come check it out, and if it's crap, you might get deindexed.
You aren't penalized, but if those links are devalued, your ranking goes down because you don't have the links to support your ranking. You had links that no don't exist, of course your ranking slips.
Deindexing is completely different, and means you can't find your site using the site:example.com command.
If you haven't tested your opinions, at least state that these are your opinions.