In political rhetoric, it’s common to coalesce a group based on shared dislike; defining the group by what the group is not. On the pseudonymous internet, it’s particularly easy to create a persona that is more like a missile launcher than a person. The persona spends all day attacking some group of people which is not part of the group, using some mixture of mockery, criticism, and scorn for the general entertainment of all who read it.
This behavior is not particularly limited to the political left or right. It seems to be a human universal which hardens group sentiments, informing members where the lines are drawn, and passing the time besides.
The difficulty for such groups comes when the time comes to actually try to form something positive. A group unified by shared criticism is rarely on good footing to actually construct anything. Critics are like bandits in that they always need to be on the offensive. The second that they create something that needs to be defended, they stop being bandits. Most groups don’t make that transition successfully to stationary banditry, because managing the complexity is too hard, and it requires a different sort of mentality than the purely negative one.
Not everyone can shift away from the mindset of taking constant pot-shots at the hated enemy, especially when you’re in the political opposition, and have no territory to protect, no policies that can be criticized, and no weighty decisions of your own that you have had to make. Uncrowned heads are not burdened by the responsibilities that comes with power.
This tendency becomes more acute under universal suffrage, because everyone is encouraged to have passionate political opinions, whether or not those opinions are informed. Most people in the US don’t bother with this, but some large fraction do. The ideological content of those opinions is often non-existent or vestigial, in that few know much of their origins, or have integrated it into some system of thinking. It is instead more like being a fan of a sports team.
To go back to the title, the negative pose in a critic creates an impression in the observer that there is nothing there. The critic is a disembodied voice (even if you can see him speak) which represents nothing but an attack on the existing order. Whether or not the attack is justified, he keeps the focus of the observer on the target, rather than the person doing the attacking.
All human groups are political, and successful political groups have some mixture of builders and fighters. Critics are like homeless fighters, mobile bandits, generally because they have lost some sort of previous political struggle, or have otherwise inherited defeat, and are either unwilling or unable to join the dominant order. Different groups employ ideology as tools to meet their ends; and those ends may have reasons behind them, but those reasons are not necessarily rational — revenge or chips-on-shoulders is sufficient motive, or greed, or envy, or a sense of justice, or pure spite.
Thinking about ideology in this way helps to expose the men behind the voices, lays out the strategic map, and gives us a better sense of who is opposing whom and for what reasons. Ideology ought to be evaluated on a similar basis to a tool, like a rifle or a shovel. Is the tool an effective implement for achieving the given end? Is it the right tool? Are the people seeking to use it qualified to use it?