That article doesn't say anything about doctored images of beheaded babies...

Yes it was widely repeated by a complicit media apparatus and the political class that supports Israel. That doesn't even mean it was believed.

In addition, after Biden claimed to have seen evidence, his staff almost immediately jumped in to later clarify that he had not. The most likely explanation is that Biden is a senile rabid Zionist who is only vaguely aware of what is happening and just repeats the same patterns he has held to for decades.