‘disgusting’… 
They not rapidly turning into plus shares - they’ve been there a while, have you only just noticed?
The rules are clear:
Free
- FTSE 350
- FTSE AIM 100
- MSCI US Prime Market (the 750 largest companies listed on major US exchanges)
- IPOs, SPACs, and other highly-requested large cap companies
- iShares, Vanguard, and Invesco ETFs
Plus
- FTSE All-Share
- FTSE AIM All-Share
- S&P SmallCap 600
- Plus any other highly requested small and micro-cap stocks not included in these indices
- All other available ETFs