An E190 on approach (remember, this airplane was trying to land at Grozny) has an approach speed between 125-145 knots (depending on load). A Cessna 172 for example has a cruise speed of ~120 knots and can cruise up to 10k feet. A typical instrument landing glide path is 3 degrees - that intercepts 10k feet at ~60km out.
The likelihood of confusing a regional jet with a small prop plane (purely based on speed/heading/altitude) is way higher during landing.
literally small prop planes with guidance systems and instead of ~4 passengers it's lots of explosives. commonly used against Russian oil depots, etc.
small radar signature, and a lot of ambiguity with civilian aircraft.