"Is this principle or opportunism?" is an extremely pertinent thing to ask when confronting any kind of proposal or plea. In other words, does the person really believe in this on its merits, or have they ran the simulation in their heads, taken note of where that would put them, and are now pushing the idea that would get them there?
For example, an ardent supporter of tax reform who strenuously argues that the cutoff should be such-and-such is someone who should be paid much more attention to if they're advocating to increase taxes on the rich in such a way that it results in their paying more, over the rich person who argues we shouldn't be taxing the rich.
Not completely unrelated: In the bad days of the late aughts when software designers were beginning to be deified and given way too much inscrutable power to make dubious decisions, I came up with a simple litmus test that could be applied to determine whether one's stated justification was horseshit* or not: it's to ask them, "In all your time as a designer where you have justified your decisions on the basis that the new way is better for the userbase as a whole—and so individuals who don't like the new defaults need to sacrifice for the greater good—are there any instances where you have undertaken a change where the result was you being among those in that instance who were negatively impacted by the change?"