Interesting link Danny. I don't work in battery design and production; I'm in the use and maintenance end. The info in your link is the first time I've read that type of advice. It is possible that those in the battery/charger production and sales side could have different goals and motives than those in the use and maintenance side.
This link is much more in line with the way I was trained in the USN and what we practice at the power plant. Granted that in my professional life I'm talking about multi cell industrial lead acid batteries in the 125 - 250 VDC range. Also, my professional experience is with relatively old technology, using batteries and chargers designed and built decades ago. The newer technology may very well have changed some of the old rules.
That said, I've always treated my vehicle and storage batteries like the ones at work, and I've had several last over 10 years. I think its unlikely that a high charge rate will be
unsafe (unless the charger has some serious malfunction) but my training and experience is that consistently charging a battery at a 1 to 3 hour rate will shorten its performance and life. And I personally have no need to do so. My 2 A charger will restore a dead 35 A-hr battery in 17.5 hours. But my battery is never dead - I discharge it half way at most, meaning I need to restore 17.5 A-hr or less, which will take 9 hours (or less).