Does immunity to Exhaustion generally gives immunity to forced sleep?

There's only 1 source that I could find that makes this explicit: the Sleep spell, which explicitly mentions who is immune to it.
However, Symbol and Eyebite don't mention any immunity, and the Adult Brass Dragon doesn't mention any immunity either, despite all of these being called "Sleep".

In the case of elves, it's pretty clear cut, they have the "Trance" trait which gives them blanket immunity against all forms of magical sleep (dragon breath aren't magical effects, though). Warforged also have the similar "Sentry's Rest".
But for the Undead, the idea that Immune to Exhaustion = Immune to Sleep is only ever mentioned as a limitation of the Sleep spell. It is not a general rule. For everything else, it's the Unconscious condition they would need immunity to, which most Undead don't have.

This feels like another case of "magical darkness" where it feels like they should all block Darkvision, but really only the Darkness and Maddening Darkness spells do. 
Unless I missed something?

Exhaustion immunity does not give immunity to forced/magical sleep - it's a specific caveat of the Sleep spell.

Exhaustion as a condition is a measure of fatigue, which can be caused by lack of sleep, but can also be caused by things like environmental hazards and starvation. Immunity to Exhaustion just means that you shirk those factors, so Undead aren't worn down by lack of food, extreme temperatures, etc.

Likewise, species like Warforged and Elves are still susceptible to the effects of Exhaustion, even though they can't be forced to sleep. The two are unconnected.