I used to drink tea only when I was sick, but then I moved to Scotland for a year and now I drink daily, however I prefer strong tea, green tea is too light for me. I wouldn't take everything on that page too seriously. For example one of the articles says that milk can cause iron deficiency anemia. It's a known fact that milk inhibits the absorption of iron but saying that it causes anemia is a bit too much (tea also inhibits the absorption of iron for example). The studies that are mentioned in most of the articles are valid however most journalists and even more webmasters can't interpret the results of a research paper on the epidemiology of nutrition correctly. For example they don't understand that epidemiological studies CAN NOT prove causality or what potential confounding factors weren't controlled etc.
Tea should be incapable of doing any harm. But, of course, your body may react to it in different way. Some people respond to caffeine adversely, and if that's you, then stay within your comfort range. I love tea too