I think there is not much reason to be mad at any operator charging money for early (ie before initial contract end) SIM lock removal.
Reason for that is simple: You were given a discount that depends on the initial value of the contract you got the device with. Without SIM lock, the device would have costed you much more.
That sounds fair to me.
If you do not want a SIM lock, just buy without a contract. Those devices should be SIM lock free (ask beforehand) or can be made SIM lock free for an administrative fee (of ie 15 GBP / 25 euro).
I bet the above difference between the situations (15 GBP, 90 euro, 120 euro) can be led back to this theory.
You might get lucky beforehand by removing the SIM lock (which is NOT illegal) yourself (with software, a hacked code or 'some' luck)
HTC Vision (Desire Z) with 13th Gen Dual SIM on TMO and Voda
Previously owned MDA Vario IV, MDA Vario and MDA II