Yes, it could be a military coup. It could also be the US using classified alien technology they found in the Bermuda Triangle.

But the simplest explanation is that Trump / Rubio were angry at Venezuela, their generals told them a ground war would be Vietnam 2.0, and that it would be safer to kill / kidnap one of their leaders and declare victory. The US can do this - Venezuela has one modern Russian-made air-defence battery (see MarmiteLover's posts in the news threads) and that can't cover the entire country. (Older systems won't work against the modern US military.)