Skynet's hard work makes no sense
Think how hard Skynet has to work to create 'infiltration units' that have 'sweat, bad breath and everything'.
Surely the reward has to be worth all that research and development, surely?
But look at how much Skynet benefits from creating 'humanlike robots' (still not cyborgs!).
They can get through the badly-guarded door maybe two seconds faster than if they just flooded that place with a big squad of efficient battle robots. Yeah, you get 'slightly faster entry' to a base you already know the location of, so you could bomb it, you could shoot poison gas into it, you could send all kinds of destructive things into it..
But instead, you create an OVERLY-complicated 'infiltration unit' that's just gonna shoot everyone openly and indiscriminatorily anyway?
What's the point?
When Skynet started researching 'infiltration units that NEVER ACTUALLY INFILTRATE', it didn't yet know that it would send one (ONLY ONE!!?) back in time, because it only did that after it had basically lost the war and humans would've won without that time machine ploy (and did anyway).
This means, it's irrelevant that it can go to 1984 and somewhat seem 'humanlike' enough to not be immediately detected. It's even more irrelevant, of course, because even this unit does NOT infiltrate anything, but BRUTEFORCES everything in sight from the second it detects people until the end.
The only time it tries to 'pass off as human being' is when it's either on the phone, or trying to get into the police station. That's about it. The rest of the time it acts like a BATTLE ROBOT, so when it also looks like one, it's kind of a really crummy infiltrator.
I mean, would anything be drastically different, if it DIDN'T sweat or have bad breath? It's flesh is shown to rot in one scene already, so its cover would be blown anyway. Even the scenes where it doesn't immediately murder someone or shoot or maim everyone and everything it sees or touches, wouldn't be THAT different, would they?
For example, the gun store scene - instead of peacefully making the store owner give him different guns and listing things, the owner would probably panic and try to flee, and the robot could easily catch him and kill him, THEN do all the gun stuff.
It spends most of its time either inside a car or on a motorbike, or destroying or murdering, so what's even the point of it looking like humans, let alone have it be such an accurately detailed depiction?
It could wear a friggin' hockey mask and everything would pretty much play out the same!
So why the HECK would Skynet work SO HARD to research, develop and create 'infiltration units', when they never INFILTRATE anything?
When you think of 'infiltration' in such a situation, you'd think it's like a 'comrade' that looks and moves like the humans do, to gain sympathy and trust, to then be able to acquire the intel it needs about the bases to kill the people.. sorry, terminate the people, and win the war. It would be like 'one of the guys' until it's time to 'betray' them and call in the attack squad or something.
It'd be like Cypher in 'The Matrix', but in a larger scale.
Did the writers even know what 'infiltration' is supposed to mean? It doesn't mean 'can't fool the dogs at the door but they will open it anyway because I have bad breath so then I can just start blasting immediately'!
Sheesh.. it makes NO sense, but then again, what does?