Eh, Simmons isn't perfect, but I am taking his side on this one. Doc/Embiid threw him under the bus, he decided that it wasn't the right environment for him and requested a trade. Then, they didn't trade him, while at the same time fining him for missing games. Usually in a situation where a player has requested a trade, the team will tell that player to stay home until they have found a suitable trade partner (while still paying them in the process).
If I were a player, I would think carefully about whether or not I wanted to sign with Philly; they might hold you hostage and make you a villain to the rest of the world. Nobody would think anything if Philly had, you know, just traded the guy.