The problem here is that this hobby uses the word "cycle" to mean vastly different things.
In the old days, when we didn't have access to (or even know about) live rock, you started with a totally sterile environment. "Cycling" meant slowly growing out your bacteria population until it was big enough to handle your nutrient load. It was absolutely a requirement, with good reason.
Now, when people start tanks with live rock as a default, people still talk about "cycling" a new tank. However, in most cases, the required bacterial population is already present, and the "cycling" process is either establishing far more bacteria than you need in a new tank, or the word is used to refer to a process that is utterly unrelated to the original meaning - processing the waste from dieoff as things on the rock slowly decompose. In the (common) scenario where someone gets relatively healthy rock, they don't need to establish bacteria, and there is no dieoff, so when they try to "cycle" the tank, nothing happens. Since people have been told over and over and over again that YOU MUST CYCLE A NEW TANK, they either worry that something is wrong, or they add canned bacteria, or they add ammonia or food, hoping to finally trigger the cycle, when in fact the tank was all ready to go right from the beginning.
I hate to even say this around here because it flies in the face of convention in this hobby and can be taken out of context, but I haven't "cycled" a tank in probably 10 or 15 years. I put in my substrate and rock, add water, wait a few days for things to settle in, and start adding livestock. I know that as long as I'm starting with a reasonable quantity of healthy rock, things will be totally fine. Generally, I use mostly clean sterile dry rock, and a few smaller pieces of "real" live rock from a known-good source.
