bitcoin can not be blamed for this, without any bitcoin pedophiles can still buy online images of child sexual abuse by other means of payment.
There are some attractive things about Bitcoin that fiat lacks which makes it more suitable for these sorts of things. With the exception of cash, fiat currencies are inherently traceable whereas Bitcoin can be made almost untraceable using mixers. More importantly, electronic fiat is tied to real-life identities whereas Bitcoin addresses aren't. It would be trivial for a government or bank to trace the real-life identity of someone who sends or receives a fiat transaction into their bank or PayPal account but Bitcoin is pseudonymous and decentralized. The most that a government can do is sift through the blockchain in the hopes that one of the senders/recipients messed up or was careless with their security.
Without an internet trail, many paedophiles might never be caught.
Let them do that, it just makes it easier to catch them.
Most of these people think Bitcoin is anonymous, and that acctually help law enforcement agencies to track and trace them.
They might think Bitcoin is a safe heaven, but the people on Silkroad thought that too, until they got busted.
Obvious honeypot to get paedos to use traceable bitcoins like the DEA tried to do.
Actually if the bitcoins were properly mixed and the owners had good security practices, never reused addresses, etc. then it would be very difficult to trace the coins. If they had exchanged them to anonymous altcoins and then converted them back into BTC then it would probably be near impossible.