It is because a black hole is so powerful, that nothing can escape it. Not even light itself can escape a black hole… Therefore, it’s called a black hole. So if Light cannot escape it, and light speed is 186,000 mi./s, then no object, no matter the size can escape it if it gets anywhere near the vicinity, And to answer your question more specifically, the power of the black hole stretches the object as it approaches and pretty much tears it into pieces as it is sucked into infinity. They call it a singularity.
