Wait, why? Bleach is a common way to kill plants in the short term without any long term lingering effects in the soil since it decomposes into salt and water. With enough drainage, the salt seeps out and plants can grow again. I'd say it's a pretty pragmatic solution to ensuring that someone doesn't grow anything again in the short term.

People drink bleach to avoid a life saving vaccine.

In this parody of a world we live in I say it is not so far fetched someone would do this.