Completely absurd.
A simple search of the effects of freeze-thaw cycles on soil quickly gave me this:
================== Secondary Frost Heave in Freezing Soils by Christopher Noon A thesis submitted for the degree of Doctor of Philosophy University of Oxford
1996Frost heave is responsible for numerous environmental problems including damage to roads, pavements and the foundations of buildings. Other less obvious problems are caused by the weakening of ground when a frozen soil, especially one which has heaved, thaws. This occurs because frost heave and freezing of soil in general, induces a moisture flow up towards the freezing front thereby increasing its frozen water content and dramatically decreasing the frozen soil?s permeability due to a decrease in water fraction and the presence of ice lenses. Thawing occurs naturally from the soil surface downwards and hence the thawed soil can become saturated causing it to suffer a complete loss of strength.
Anyone who lives in (at least) the northern 1/3 of the US and all of Canada knows that when walking on your lawn in April (or in May in Canada) when the last of the snow has melted from your front or back lawns knows how spongy the ground feels.
It is a complete crock of s*it to think that aerating your lawn does anything to "break up" or "loosen" your soil under those conditions.
And take a look at this:
====================== Myth #2: You Need to Aerate Your Lawn Every Year
Aerating is hard work that requires expensive machinery. Fortunately, you may not have to do it. Aeration is helpful when your lawn has a lot of foot traffic that compacts the soil. Also, if you have a lot of thatch, or if you need to amend the soil, you may want to aerate. If not, save yourself some time and money, not to mention an aching back.
Myth #3: Gypsum Aerates Your Lawn
Somebody made a lot of money with this one. If you spread gypsum on your lawn, you'll end up with some very nice pebbles, but not an aerated lawn. =======================
Thatch removal or management is frequently mentioned as a byproduct of core aeration. What is never mentioned is that if you always bag and remove your grass clippings, you'll never have a thatch problem (and all associated problems that come from harboring various turf insects and diseases).
And to some degree the raking of the plugs that happens by people who take more of an interest in lawn care and succumb to the placebo effect of thinking their lawns looks better after coring are really just seeing the effect of thatch removal which can make an early spring lawn look much better.