Pointing out capture and defend points is not treating players as if they are devoid of intelligence. It's just a helpful way to keep players informed of how the current game is playing. Most of the complaints I've seen are over the size of the text, not specifically that it's there. Previous Halos have had flag indicators and flag status UI (Halo 2 even has a red flag icon when your flag is away under the reticle).
I'd rather people know what the game wants them to do than hope they've had enough experience to learn the flag spawns and status of 100+ maps by heart.
I've mentioned this before, but I've always felt if Halo 4 just had the weapon spawn indicators, that would have been a pretty cool upgrade for the UI. It doesn't need to be attached to the global ordnance system.
Also, spawning rules can be inconsistent from map to map in Halo games. How many people know which maps in Halo 2 let the sniper rifle respawn, and which ones don't? Learning spawns doesn't mean much if the spawn rules aren't even consistent. I remember all the spawn times and spawn rules of Halo 2's maps (sans the PC ones), not everyone has that halo-nerd-level memory vault.
Amusingly, "let them play 1-2 games of CTF" is the average statistic of how many objective games someone will play in previous Halo games before giving up on a playlist and never coming back that has mixed obj and slayer. It doesn't help that people will use objective as a chance to grief players, either.