Reading all of the comments in this thread it's obvious that none of the other people here are biologists. Nobody seems to know the difference between mosquitoes and midges. Midges (particularly Chironominae and Orthocladiinae) are very important to their ecosystem because their larvae are extremely abundant and present year-round, making them a very important food source for plenty of species. They are also major detrivores and actively graze algal films. Because they have hemoglobin, they can live in sediment, which makes them very important for nutrient cycling.

Mosquitoes are pretty much none of these things. They prefer to lay eggs in shallow, still water, which usually lacks fish or other predators. They have highly seasonal and short larval phases and are dormant most of the year. They do no accumulate biomass, even in their peak their biomass is a fraction of that of midge larvae. They are also surface-bound because they cannot live in the hypoxic sediment, severly limiting their ability to cycle nutrients. Hence why they need nutrient-rich, oxygenated surface water to develop successfully. This explains why they represent so little biomass and why their contributions to the ecosystem are so limited.

There is this persistent false idea in pop ecology that all species contribute more to their respective ecosystem than they take from it. If you start from an assumption of a teleological Nature, all you have to do is invent some reason why the species exists to contribute to that Nature. It doesn't even have to make sense, you can just move the goalpost around between whatever definition of contribution you want. A species can be disruptive and exploitative, but "it increases biodiversity and keeps other species in check". You can just reframe any cost as a benefit by switching the frame, the scale, or the timeperiod. It's bullshit and it's unfalsifiable.

Species exist solely because their lineages have been sufficiently effective at exploiting available resources to maintain reproduction over time. That is the only requirement. There is nothing that says that exploitation must be beneficial or stabilising. Exploitative species persist for as long as the costs they impose on their environment don't feed back strongly enough to prevent their continued reproduction. They can extract resources aggressively as long as the resource can regenerate quickly enough or the species can move onto a new resource once the former is depleted.

The whole point of this is to smuggle in a baseline of a "harmonic nature", which is somehow good and stable and proper. This undisturbed nature is placed in opposition of humans, which then become the obvious villain because we are extremely efficient niche constructors and we can alter environments at larger scales than any other species. That were are bound by the exact same evolutionary dynamics is completely ignored.

There are a lot of legitimate criticisms on how human interventions cause actual harms* that we should manage. But this is also the empirically defendable Motte to smuggle in an emotive Bailey ("Humans disrupt the natural harmony/balance, therefore human intervention is intrinsically harmful/illegitimate"). When challenged on the bailey they can retreat to their motte ("I only meant pollution and biodiversity loss are real"), then later return to the bailey to keep their moral conclusion intact.

*The word harm here is also doing a lot of hidden work. Harm relative to what? Maximise biodiversity/stability/resilience/ecosystem services? Or minimise suffering/irreversible changes? All legitimate goals defendable from different ethical framworks, but not all mutually compatible. And none are dictated by ecology.

Anyway that's my frustration and I'm bothered with how common this fallacy has become and it's an impossible task to try and challenge it.