Well, I can't say I've heard that argument made, either.
Not only such argument was used in this thread (by BADdecker, but by now I've learnt to take what he says with a grain of salt) but also on the sites I originally linked.
But why don't you define what you mean by these two terms, global cooling, and global warming, so that we are not just talking about different things but thinking they are the same. To me, there are cooling influences and warming influences on climate, and they sum each day to net effects. Thus it is nonsensical to deny one, or the other. But these influences would have to be against some standard, since "cooling" and "warming" are relative to something, right?
In here lies most of our misunderstandings, I'd reckon.
Global warming & cooling to me climatic trends, which indicate whether the average world temperature is rising or decreasing, and therefore to claim global cooling exists is essentially to argue the world's temperatures in the long term are decreasing.
Naturally there are cooling & warming influences, but these are factors that feed the pattern and not the pattern itself.
What, then, is the equilibrium temperature of the Earth?
That question is more complex than it seems. What would equilibrium temperature mean? Which sphere of the Earth System is being accounted (I'm assuming only the atmosphere)? In which time scale? And, lastly, I don't see how knowing that would contribute to the conclusion there is/isn't global warming/cooling.
See the "Global climate" section of "1883 eruption of Krakatoa" (https://en.wikipedia.org/wiki/1883_eruption_of_Krakatoa#Global_climate). There are more global cooling writings about times before Krakatoa... back as much as a thousand years. Do your own research.
A punctual event is irrelevant. That's the equivalent of me pointing at Australia and saying "See, global warming's so bad that it has exponentially empowered natural/artificial forest fires! Do your research
". Sure, one is a product of the other, but it's one out-of-the-curve catastrophic anomaly rather than the norm. Besides, can you point studies that sign current or future volcanic activity is so high there is a chance of global cooling?