I'm pretty sure the idea that only half of it is taxed as Texas earnings is wrong. Players are paid by the day on the active roster not by the game, so it's not as simple as half and half and for Methot in particular, if he's rehabbing from injury during a lot of this time and spending it in Dallas, he's not being taxed on any of that.
Players are taxed in different ways.
A player is taxed in the city they play. This is the jock tax. But a way that players avoid jock tax is they take a lower salary and higher signing bonus. Bonuses are taxes at the players place of residence.
For example:
Player A, signs a 5 year $25M contract. The structure is that they player gets paid $1M in salary, and $4M in bonus paid on July 1st. This player lives in Dallas.
Player B, signs a 5 year $25M contract. It's all salary. $5M a year in salary. This player lives in Dallas.
Player A, will make more money. This is because $4M is taxed at the federal rate, and half (in reality slightly less than half) the salary will be subjected to the jock tax around the league. Player B will be taxed on his full salary of $5M in cities.
In Methot's case of being at home, living in Dallas at the time, means his full payout wasn't subjected to income tax and was only subjected to federal tax.
It's kind of disingenuous statement for him to make without clarifying.
That's like saying people should be pissed at Auston Matthews because his primary residence is still Arizona, meaning because of the tax treaty of America and Canada means he pays less income tax since almost all of his contract is signing bonuses.
The issue isn't no income tax states, it's the fact players can avoid the tax simply by not living in the city they play for and taking a signing bonus heavy contract.