Sell to buy isnt a thing. What you’re describing is player trading which every single club in the world does. Are we selling Pickford Walcott Tosun Gueye or Coleman? Doesn’t look like it, which means we are selling players we don’t need, like every other club tries to do. What do people want? Keep all the bad players and buy even more players? People just love the ‘sell to buy’ stick to needlessly bash Everton with.
Sell to buy certainly is a thing. It remains to be seen whether that's the approach we're taking (personally I doubt it) but it's pointless saying it's not a thing because it's totally different to player trading.
Player trading, as you rightly said, is what all teams do. It's buying player A, B and C, and selling player X, Y and Z. That's standard, and nobody has an issue with it. Sell to buy is when you can't buy A, B or C
unless you sell X, Y and Z. There's a big difference. It also means if you don't get willing buyers for X or Y, you might have to sell player D and E.
As I said, I don't think we'll be following a sell to buy model, but I can understand why people are concerned when those words are used.