One that is enforcing the documented airline policies, which is in compliance with the ATA Customer First initiative.

See the "Any change to this reservation (including flight, dates, or cities) is subject to a $150.00 change fee per passenger. The new itinerary will be priced at the lowest available published fare at the time of change, which may result in a fare increase."

just above the "I agree to comply with the terms and conditions applying to this ticket. "

Like or don't like the policy, but I can't see a valid complaint that they are unwilling to break their documented rules. Other airlines' policies don't really have a bearing on their decision.