These are the most prolific genres of criticism against Marx, and they're dumb for their own reasons. But there is a third, elite kind of criticism so catastrophically stupid that it doesn't fit into either of those categories: points that wouldn't work as criticism if true, and that aren't even true. For an example of this, consider the idiotic attack trending on Twitter right now:
LOLing at all the morons tweeting #ResistCapitalism from their capitalist Twitter accounts on their capitalist smartphones.The premise here is straightforward: there's something hypocritical about Marxists who use technology that was invented within Capitalist economies. The problem, of course, is that this is not actually true -- and even if it were true, it would say nothing about the merits of Marxism. Suppose that there are Marxists who actually are hypocrites. What exactly does this prove about, say, the labor theory of value?
— Michelle Malkin (@michellemalkin) April 25, 2015
More to the point, the argument that Marxists should not use technology invented under Capitalism relies on premises that Marxists openly reject.
Simple example: Capitalists maintain that the economy is governed by the "law" of supply and demand. Products are supplied and produced in certain ways because that's what consumers have demanded; so if you buy a product, you are responsible for the way it is produced. Thus, if Marxists buy cheap consumer electronics or clothes made in sweatshops, they have no moral standing to complain about exploitative business practices.
Marxists would indeed be hypocrites if they agreed with this line of reasoning and yet still chose to buy products produced within a Capitalist economy. In that case, their actions would be inconsistent with their beliefs, and critics would be right to draw attention to the discrepancy.
And yet Marxists quite obviously do not think that the economy is defined by supply and demand. That is precisely what Marxists are arguing against. Marxists insist that no amount of conscientious consumption can resist the overwhelming, systematic incentive that employers have to exploit their workers. For that reason, the choices consumers make in the market are completely irrelevant; they are not what causes exploitation, and it will continue with or without them.
The honest critic of Marxism should at this point simply maintain that the law of supply and demand holds, and that Marxists who reject it are in error. But this is where the "hypocrisy" allegation becomes truly bizarre: because instead of acknowledging the disagreement, Capitalists pretend that Marxists actually agree with them about the market, and are exploiting workers anyway. That is a patently insane, bad faith premise - but it is the only basis on which the hypocrisy charge can make sense.
This general problem besets the "hypocrisy" complaint from every angle. Marxists do not believe that you can fix Capitalism by being a good consumer. They don't believe that technology produced in Capitalism could only have been produced in Capitalism. They don't believe that you can simply excuse yourself from the Capitalist economy, either. Marx is quite clear about all of this: people who are born in a particular historical moment and in a particular economy have to play the cards that they are dealt.
Thus, this point falls into the elite third category of dumb anti-Marxist criticism: Marxists who use technology aren't hypocritical, and even if they were that would prove nothing about Marxism. The point does, however, demonstrate something about the Capitalist. The assumption that Marxists agree with them about supply and demand is at best dishonest. At worst, it demonstrates an extraordinary intellectual failure - a complete inability to evaluate the world from a different perspective, even provisionally. That ability, of course, is the basis of empathy, so its absence among Capitalists is not all that surprising.