The only party to blame for SEO is Google. Everyone else is just playing catchup to however they decided to rank pages this week. There are other search engines, of course. And no, don't stop using Google, but also start using the alternatives. Just using one search engine is doing yourself a disservice.
How is it free? When I try to download one of those scores, it tells me I have to subscribe. And "try for free". Why? What is that? They don't mention a price, but it strongly suggests I have to pay sooner or later. That's not free.
Plus, they have a ton of non-PD scores for which they don't pay licenses. They just grab the money.