Respectful rants always are fine and I appreciate where you’re coming from 
There’s a lot more detail on the practice and its uses across financial services businesses on a landing page we created ahead of this terms update.
The biggest lenders of shares in the market tend to be pension funds and long-only funds (including ETFs). Retail brokers also do lend out customers shares held in nominee accounts as a source of additional revenue, in a similar way that we (for example) generate interest on cash held in customer accounts.
On the point about different account types it’s worth pointing out that we cannot (down to HMRC rules) lend anything held in an ISA.
Beyond that, I’m going to close this thread and would suggest you post any further questions on the main thread here. There’s been a lot of discussion and we’re happy to jump in with further answers as needed!