I agree with
SK AAR ,
I don't find it ethical for a company to provide a huge gesture and then limit it stating the rights that they have the option to change the T&C's.
However, let's don't forget that they are still offering the most generous rebooking policy across airlines.
Also, for the 5000-mile policy, they clearly stated in the initial T&C's that this was allowed for changes
made up to 30 September 2020 and
for travel until 31 December 2020.