Earlier quoted context omitted.
This is a rhetorical trick that people have been using for a long time. The Thinker takes a bold and shocking stand, which is compressed, by the rules of memetic natural selection, into the boldest and shocking-est possible framing: "People don't actually care about their children." Or "Truth doesn't exist." Or "We should kill poor people to increase the average level of happiness." People are instantly nerdsniped by…
You seem to have exaggerated the 'stands' you give as examples. The problem with that is that I'm instantly reminded of all those times where I've seen critics of some 'Thinkers' accuse them of taking 'stands' like these, and after more or less digging (depending on of unpopular they were) it indeed ended up being either words taken out of context, or just strawmen.
To say that X is a "strawman" implies some degree of disingenuousness, some intentionality, as if you could only possibly believe that Robin Hanson thinks people don't really care about their children if you are actively trying to misrepresent his real stance, which you secretly know deep down. In reality, Robin Hanson actually does think that people don't care about their children nearly as much as they say they do, add six more pages of caveats. This gets rhetorically rounded off to "Robin Hanson thinks people don't care about their children." The result is endless stupid conversations. This may or not be partly Robin Hanson's fault for making his blog post titles intentionally inflammatory and attention-grabby ("Healthcare is not about health", etc.). I am agnostic was to whether Foucalt has intentionally turned into the skid on this; but I do personally suspect that many big thinkers lean into obscurantism because they don't want to be nailed down.
Another way of phrasing the above: What you just posted is actually my point. On reflection, I'm not actually sure whether you read beyond the second paragraph.