The word legitimacy can be interpreted in either a normative way or a “positive” (see positivism) way. The first meaning refers to political philosophy and deals with questions such as: What are the right sources of legitimacy? Is a specific political order or regime worthy of recognition? As such, legitimacy is a classic topic of political philosophy.
While I agree with you that it would be incorrect to baldly dismiss Truss' premiership as illegitimate, I feel that uniqueuid's comment was using the term according to the above usage, suggesting, perhaps, that the law of the land is anachronistic, or less than optimal according to democratic principles.
https://www.britannica.com/topic/legitimacy
While I agree with you that it would be incorrect to baldly dismiss Truss' premiership as illegitimate, I feel that uniqueuid's comment was using the term according to the above usage, suggesting, perhaps, that the law of the land is anachronistic, or less than optimal according to democratic principles.