Irrespective of whether he was visiting (and contributing money to) a child porn site for research - the truth is that he was looking at(and contributing money to) children being exploited. As a parent, I find that hard to justify. "Writing a book" is not some heroic crusade whose end justifies any means. The fact that he paid to view means that he cannot argue that his actions did no additional harm.
If I go and mug an old lady then can I use "research" as a defence? I doubt it.
He is clearly guilty of the offence, by his own admission. The important question is whether he is a paedophile & whether he will continue to feed that cess-pit. At the very least he is now a very suspect character - and rightly entered on the sex offenders list.
Generous spirited as we try to be - "innocent until proven guilty" is a risky approach to take with paedophilia.
Paedophilia is a horrible demon to wrestle with - and if Townsend does have that tendency then I wish him all the luck in the worl in conquering it.