Devs missing deadline because they fucked around, or under estimated the work required and didn't budget themselves enough time is more there fault (assuming the reason they under estimated wasn't lack of information from management). Devs missing deadlines because someone tells them Tuesday that they need to drop everything and pick up a 5 pointer and have it done by Thursday, is management's fault. The "unrealistic" part of the "unrealistic deadline" was the key word there.

Here is a real life example for you. Last year we had a few tasks for migrating our logs and dashboarding from Datadog to Dynatrace. We had just gotten our logs routing to Dynatrace on Wednesday, and were going to start work on migrating our dashboards (or actually rebuilding as there was no way to directly migrate them) the following sprint.

Then on Friday, I get an angry call from a manager of some other team that had some responsibility over the Datadogs licensing asking why we still have logs routing to Datadogs. She says that the license is being hard shut down on Monday and we need to be migrated already. So I had to drop everything. I had to export everything we had in Datadogs, and start manually rebuilding in Dynatrace (which uses a poorly documented proprietary query language I'd never used before), prioritizing the most important stuff for our support team before the weekend lest they fly blind starting Monday morning.

I only found out on Monday that this manager didnt know what they hell she was talking about, that we weren't on the license being ended, and we had another month to do the migration. I was treated like a fucking champion by my own manager, who had been out of office on Friday, for getting done as much as I had in a single day, but there was no reason for it. She was misinformed from bad communication. And even if she had been correct, her lack of observation on the matter earlier and only informing us about the issue at the last minute was inexcusable. So was her anger over the situation at our team, who doesn't fucking work for her, btw (not even sure which team she's over), for not falling in line with a deadline we didn't know about, or as it turned out a deadline we didn't even have... bad management.

Most devs absolutely suck at estimating the time involved in a task. If management is setting deadlines by asking “how many hours will this task take” then missing a deadline is on management.

It's more that the consequences of a management fucking-up have many times the impact of the consequences of the fuck-ups of individual members of the team, because a single manager's choices impact the work of multiple people.

Further, managers who do things like setting the deadlines themselves, actively pushing the devs to lower their estimates of the time it takes to do something or, even better, actually take a junior developer's estimations at face value, are the ones responsible for the deadlines and thus to blame when they're missed - if in some way or another you forced certain deadlines on the team or fully trusted information from the least knowledgeable, it's on you, not on others.

Some managers are actually pretty good in that they don't do that kind of shit and even properly manage things like client/external dependencies, but in my experience they're a minority.

Granted, when the deadlines are missed for such managers it's not usually their fault: sometimes it's the devs' fault and others the fault of somebody upstream in the process (such as the client, an external provider or a business analyst).

That said, I can see where the stereotype about managers fucking up projects would come from, especially in certain countries where the management culture in Tech is one of bullshit, incompetence and even bullying, so they have way fewer competent managers and way more abuse than countries with better management culture in Tech.