Because I've read enough panpsychism (not Strawson directly, though; I've only read summaries of his arguments--I have read articles by Goff, though) to know that it isn't a straw man attack. (Besides, my strongest "attack" is saying that if you shoo physicists away as irrelevant then you're committed to just making stuff up and not letting people test it.)
Panpsychism is fundamentally an attempt to explain an observation about the world, which is that we have consciousness (we think--we might, of course, be rather confused about its nature, but it seems hard to envision a way that we could be wrong about it existing at all). If it's not going to explain that, it's utterly pointless--you can layer on any number of alternative qualities that make no difference, and which cannot be disproved or proved. We typical reject those with "why bother?" a la William of Ockham.
Panpsychism isn't like debates about scientific realism vs anti-realism etc., which don't actually hinge on any observations but rather explore what attitude we should take towards them. If Hossenfelder wants to weigh in on that, I would strongly recommend that she do some reading (Quine is good background)--though anyone can argue against some of the less thoughtful types of anti-realism that don't account for our inability to whimsically decide that reality is different and proceed without dire consequences.
Panpsychism isn't like debates about interpretations of quantum mechanics, because the whole point about the Copenhagen vs other interpretations is that when you ignore them all and just "shut up and calculate", everyone gets the exact same answer.
No, Panpsychism is a substantive physical theory precisely because it appears to explain phenomena in the physical world. To not, it has to deny that consciousness can be causal (despite reams of evidence that it seems to be), and that it only explains this curious epiphenomena that we feel and...um...talk about...physically moving our mouths and...awww, dang it.
There are possible rejoinders to Hossenfelder's criticism. But they've got to be based in physics, not in philosophy, or panpsychism loses its reason to exist.
Honestly, the quality of argumentation I see from most modern panpsychics is embarrassingly poor. Neither anti-emergence nor intrinsic-nature even make it past the sorites paradox. (Pan-pile-ism: the idea that in every grain of sand is some pile-ness, and that piles are unintelligible otherwise.)