The idea that bleach can linger in wood neads a bit of thought?
Simple bleach of the type we use, without color or scents, is made of three things, water, a form of salt, and chlorine. Can we accept that water and salt are okay but the chlorine is the thing we worry about?
So what can we find about chlorine? It is normally a gas and we have to do some tricks like tie it to salt to keep in the water longer so we can store it for a while. We also can read on chlorine and find it reacts very readily with organics. Organics in this use means carbon bearing compounds. Not organic gardening!
So can we agree that wood is an organic? So can chlorine that reacts with organics like wood stay in wood without reacting? Once chlorine comes into contact with wood, there is a chemical reaction until one or the other is depleted.
In most cases the chlorine is used up and gone before the wood. In the cases where we splash bleach on our shirt, it is often the shirt that breaks down first!
Unless somebody can show me a chemical reaction that can lie dormant for years and then suddenly come out when we add fish, I find chlorine is totally safe to use on tank stuff.
Another good indication that it is safe is the number of experienced hobby folks who use it all the time.
Unfortunately, there are those who have not used it and continue to spread what they have been told without thinking about it or trying it.
Don't simply something like this that you find on a forum. Do some reading and decide. Reliable info is out there for the reading. Here are a couple sites to check:
First paragraph, first sentence?
It's Elemental - The Element Chlorine
Less reliable being Wikipedia but still lots of info: