Yes it is underhanded.
Throughout the season, McLaren (and probably other teams), all have an established system as to who goes out first/last in Q3.
In Hungary 2007, it was Alonso's turn to go out first and get the better run. However, Hamilton disobeyed team orders and went out ahead of Alonso. This is what angered Ron Denis.
Alonso retaliated immediately and blocked the pit area, which prevented Hamilton from getting another run of qualifying. This led to Alonso getting pole.
The FIA then got involved and demoted Alonso. Ron Denis was angry at both his drivers.
Alonso then threatened to leak info to the FIA. Ron Denis then "shopped" his own team.
It all snow-balled from there.
The fact that Hamilton disobeyed the established system, was very underhanded.