It's certainly possible that some coincidence has caused all these warmings at the same time, but it does sound like they're merely speculating on some of them, because they don't want it to be sun irradiance. Further, blaming the mars warming on its Milankovitch cycles seems far-fetched to me. For earth, at least, Milankovitch cycles run 20,000 years and longer (probably most notable at around 100,000 years, the periodicity of the last 4 ice ages). And since mars is farther from the sun and has much smaller moons, I would expect its Milankovitch cycles to be even slower. (I welcome a correction or any links on mars's Milankovitch cycles.)
Is it just me or do Milankovitch cycles remind you of Ptolemaic epicycles?