There's no need to jump in, in advance of a clearer indication of the facts.

What seems to have happened is that Pete Townshend's name was on a list of people who have given their credit card details to a porn site featuring child porn.

The list has been passed to the police in Britain by the authorities in the USA who had got hold of them and they are investigating. And someone seems to have leaked the story to the tabloid press, who have gone to town on it, but because of the laws haven't included the actual name.

Obviously the name would come out soon enough, especially in these Internet days, so Pete Townshend has pre-empted matters by going public with his version of the story.

Having his credit card details in the list could mean just that he'd typed in the credit card details as a way of having a look at the site, not necessarily that he'd been subscribing to it.
And he's said that is the case, and that he'd done so out of a wish to find out what was in the site, and with a view to attacking child pornography and child abuse.

I think it'd be quite wrong to leap to any judgements about this, because we just don't know the truth. There's nothing intrinsically implausible about that explanation. That doesn't mean it has to be true either. Anyone who gives their credit card details to anyone they don't trust is acting very stupidly, and by definition you can't trust the kind of people who'd be running a child porn site. But people do stupid things all the time, including good people.

But demonising Pete Townshend on the basis of what has come out so far would be quite wrong.