Yeah if you read my response you'd note I covered the removal side of the protection too. Remember I played with these cards in constructed formats where you'd be thinking about having to see them over and over and over. Sword of fire and ice is an issue if you've made red's removal mainly sorcery based or you involve a lot of blocking in your defensive plan for blue decks, or if removal in your cube is just awful in general (this is kinda beside the point of protection abilities though, and applies to pretty much any efficiently costed equipment, though it is exacerbated by the protection abilities further complicating your neutered removal and bad removal formats tend to rely more on blocking).
Lets imagine this without the protection: If you aren't hitting that bear with the bolt in response to equipping, the bolt wasn't exactly going to be killing a 4/4 anyway. I know it can be used in conjunction with other damage like blocks or another card, but it wasn't like you were getting rid of the equipment, you'll just make them spend 2 more mana to put it somewhere else for your 2 cards.
My line here is that the protection on sofi is actually rarely relevant to red and blue decks in any big way. It's rarely relevant at all EXCEPT when it comes to multicolour cards, where things get more complicated. Mainly you can just consider it an enormous equipment that forces your opponents to play correctly lol.