Well, I was trying to make the case that it's
not dramatically harder to take Starlink down than it was to put it up. If your barrel bomb full of nails works, that would be even stronger evidence that it's not dramatically harder.
My intuition, though, is that it wouldn't work. Kosmos 1408 became a two-tonne barrel bomb full of nails in November and so far isn't known to have taken down any other satellites.
I don't really understand orbital mechanics, so take the following with a grain of salt.
The Starlink satellites weigh 230-300 kg and orbit at 540-570 km altitude, at which altitude the thermosphere will passively deorbit failed satellites within 5 years. I think a metal object weighing 10 g, such as a nail, would deorbit about 30 times faster, about 2 months, because it weighs 27000 times less but only has about 900 times less surface area. But that's assuming the nail is in orbit in the first place. If you have a barrel bomb in LEO and you blow it up, sending the nails in every direction, most of them will immediately deorbit: those traveling backwards or down will deorbit immediately, while those traveling forwards or up will deorbit 45 minutes later on the other side of the earth.
Only a narrow plane of the shrapnel will stay in orbit at all. If the shrapnel forms a sphere around where the barrel would have been if it hadn't exploded, a plane through its center intersects that sphere in a circle. The nails in this circle will stay in orbit: some are going sideways, some forward and down, others backward and up.
The Minkowski sum of a nail and a Starlink satellite is almost exactly the same size as a Starlink satellite, so we can think of each nail as sweeping out a Starlink-satellite-sized path in its orbit. I don't know how big the satellites are, but they must be on the order of 50 liters to weigh what they do if they're mostly made of metal, which would make them on the order of 40 cm in diameter. So each nail is sweeping out roughly 40 cm x 40 cm x 7000 m/s. So over the course of two months before it deorbits, it sweeps out about 5.9 billion cubic meters (5.9e9).
If we approximate the Starlink volume as a 30 km thick sphere beginning 540 km above earth's surface, its inside radius is about 6911 km and outside radius about 6941 km. That has a volume of 1.8e19 cubic meters. So a random nail has a chance of about 1 in 3 billion of killing a particular Starlink satellite, of which there are almost 2000, so about 1 in 1.5 million of killing any of them.
From one point of view that suggests that a barrel of nails could work; you just need several million nails to kill any satellites (thus, tens of tonnes, which is feasible) and several billion nails to kill them all (which is not).
Smart and expensive killer satellites are likely to be much more cost-effective. Faberge eggs are far too simple, though; your killer satellites need to be more like the complexity of a feature phone. A feature phone controlling a Bernz-O-Matic valve, though.