There is a reasoning behind emails like the first: managerial mystique. Make decisions, don't explain why. If you explain your reasoning, there's room for debate.

You don't want to explicitly say, "Because I say so", because that's drawing attention to the fact that you're being a dick. The stuffy and bureaucratic language is a part of that. It's about seeming official. The "bad" first email is classic 20th-century management done well.

Like this:

TO: All employees [1]

After careful consideration [2], we [3] have decided to review [4] the work-from-home privilege [5] that we offer. While we intend [6] to continue extending this plan [7], we expect that employees will monitor their individual performance [8] while doing so. For that reason, we've attached form TPS-363 [9], which all [10] employees are expected to submit to their managers should they continue to use the work-from-home privilege. [5]

Footnotes:

[1] Aggressive formality. This isn't "Hey Team". It's serious business. Management is alert. The Man is on patrol.

[2] "Careful consideration" means, "We're saying upfront that we don't want to hear any complaints or dissent. We're representing ourselves as having deliberated already in an attempt to shut out any room for debate."

[3] Use "we" to communicate bad news. The "we" is a move to speak for the company so it sounds like you're ruling based on leadership rather than authority. "The company" (not just an anal-retentive manager) needs this.

[4] "Review". This makes it sound like there was a process and (again) a deliberation.

[5] Note the use of the word "privilege", subtly implying, "we can take this away".

[6] "We intend" = "We're being nice by letting WFH continue, but don't make us regret it."

[7] "Plan". Working from home is no longer something the company offers to improve productivity and morale, nor is it a perk. It's a "plan". And plans have rules.

[8] "Individual performance". Scary words that suggest more managerial oversight and possibly "reviews", "performance improvement plans", and terminations. Good employees never, ever have "performance" under discussion. Good employees (and managers who know they have good employees) discuss the impact they've had and would like to have in the future. They discuss goals and lessons and aspirations. When the discussion is of "performance", it's inherently a negative one. The stars don't need performance reviews to know they're doing well. Performance reviews are to scare the people in the middle and to document the reason for firing those at the bottom.

[9] The longer the form, the more there is a message of, "We'd actually rather not that you do this, but if you're willing to feel like you're applying for a hand-out by filling out this form, go ahead."

[10] Note the use of "all". That's most important. It makes the change seem uniform and fair, and applied across the whole company. This allows people to conclude, after a bit of annoying news, "Well, if my boss has to do it, and so does his boss, and so does his boss, it can't be that bad". Of course, the reality is that people in the managerial hierarchy (and grunts with supportive managers) can ignore TPS-363 and no one will bat an eye, but the change appears impersonal.

This is a "bad", morale-damaging email, but it's 20th-century bureaucracy done about as well as it can be. How so? Well, in a mid-20th century context, people are already used to annoying, paternalistic memos from "on high" and have developed an immunity to them. They know that companies gradually get worse, but that the process is generally quite slow. What it actually is is a dog-whistle. The actual targets (WFH employees perceived to be slacking off) of the memo are warned, but the rest of the employees forget it 15 minutes after it was sent. Do people actually quit their jobs after an irritating email? No. People grumble about them and then forget. They get back to work, and people who enjoy the work they're doing are going to annoy irritating upper management unless it directly affects them.

The difference between 20th-century bureaucratic management and 21st-century movement in the post-managerial direction (cf. Valve) is the change in the motivation-payoff curve. If a highly motivated employee is only 25% more effective than a typically motivated (i.e. wanting promotions and not to be fired) employee, then irking a highly motivated one to warn a slacker is worth doing. If that discrepancy is 5x to 10x instead of 1.25x, the calculus is completely different: you're actually better off taking a hands-off approach and letting employees self-organize (and quietly managing slackers out if they fail to find a place after a year). We're coming into a world where a company can only be competitive if its people are highly motivated, and traditional Theory-X bureaucracy just doesn't work.