Another possibility is that they're not "letting you in" to use you "as a body shield" but they're leaving a sensible amount of empty space "as a body shield" and you've just put your car in the middle of a potential collision zone.

LPT: leave a good healthy gap in front of you. Remember that "two second rule"?* Try counting it out some time, it's probably further than you think. 90+% of drivers I see are within a second, and an alarmly non-zero amount significantly closer than that!

And it's really not as patronising as it feels, either. Even if you're focussed on driving (and let's face it, it's very easy to have your attention divided or entirely displaced for short periods while driving) it'll take you about a second to respond to a sudden need to slow, so if you're within a second of the vehicle in front, there's a good chance you'll hit it even in the most favourable of circumstances.

I've had a couple of accidents where I've used up all of my two second gap and more - including one recently. Please take this seriously!

* Oh, and that's for dry roads. Double it for wet, triple it for salted, and multiply it by ten for ice/snow.