The speech Tony Abbott delivered to the Global Warming Policy Foundation in London has attracted all manner of ad hominem attacks, while few have addressed the validity of his claims.

Among the most infuriated were climate-change devotees. As the saying goes, “if you’re not getting flak, you’re not over the target”.

Labor’s Tanya Plibersek described the speech as “just nuts”. “Tony Abbott’s left the realm of the merely destructive and entered the realm of the loopy. This is actually just weird stuff from the former prime minister,” she told Sky News.

C’mon Tanya, you’ll have to do better than that! Describing the many valid points Abbott made as “loopy”, “weird” or “nuts” is not a counter-argument, it’s just ad hominem rhetoric.

Even Attorney-General George Brandis couldn’t hide his contempt: “He made some interesting anthropological observations about people sacrificing goats to volcanoes or something like that … but life is too short to read everything that all of one’s political colleagues may have to say.”

Greens MP Adam Bandt said Abbott was a “dangerous fool who could be simply ignored were it not for his ability to dictate Malcolm Turnbull’s climate policy”; fellow Green Peter Whish-Wilson helpfully suggested that the Libs should disendorse Abbott because not to do so would be “tacit acceptance of the promotion of climate-change denialism”.

Guardian reporter Katharine Murphy said Abbott’s “climate frolic is strange and sad” and “he should have been laughed out of the room”.

The ABC’s Andrew Probyn wrote, “Having drenched the work of climate scientists with contemptuous spittle, the real Tony Abbott has emerged”, but did not attempt to disprove any of Abbott’s assertions.

Reaction to Tony Abbott’s speech has been predictable: a smearing of his character rather than a genuine appraisal of the futility of climate-change policies.