A valid argument and I agree in not cancelling subscriptions but maybe for different reasons.
Personally I feel an endorsement to any candidate only exposes as bias. That would be fine if their paper was called the "Democrat Times" but it's not.
Either a media outlet is transparent about it's bias and then endorses, or it simply doesn't. You can't have any media pretend to be fair and balanced while giving an endorsement even if the reasons are right and true.
If people are to believe in fairness, transparency and balance then maybe it's better to allow people to run their business that way too.