What a lot of people miss is that IQ was devised by educational psychologists to give them a metric for assessing the intellectual development of children. The question it was supposed to answer was "Is little Johnny developing normally, quickly or slowly?".
Hence the basic IQ formula of IQ= 100% * developmental_age/chronological_age. It's quite obvious that once one has reached the age where basic mental development stops, that formula becomes nonsensical as one's chronological age will keep increasing but one's developmental age becomes fixed. Extending IQ into adulthood, and repurposing it as a measure of 'G' (general intelligence) has methodological problems, as should be obvious, but until someone comes up with a better measure of 'G' it's all we've got.
I've generally found that those who are derisively dismissive of IQ as a measure have taken a test (possibly not a good one) and scored more poorly than they'd like, and those who are fans are people who've been given a high IQ score.
People who score more highly than 3 standard deviations out are likely to be smart enough to be somewhat sceptical of the merits of IQ testing and are also likely to keep quiet about their score - they are likely to have acquired it early in education, been labelled 'gifted' and know what unrealistic expectations and pressures to 'achieve' come with other people knowing what it is. I've watched the latter from the outside and it can often turn out badly.
I prefer people to form a balanced view of each other's capabilities and not get into a game of IQ 'top trumps' - I've seen that happen too. Leave IQ scores where they belong, in an educational psychologist's office.