Earlier quoted context omitted.
Anything done excessively can be unhealthy, by definition, but there's only a grain of truth to what you're saying. To your point 1: done properly, running isn't particularly harmful to joints and tendons, and some studies even seem to show that running can be beneficial in that regard[1]. The rapid changes in direction that cause the most stress are less prevalent in running than just about any other sport, not even…
Biking, swimming, and rowing are all better on the joints than the impact from running. >P.S. Instead of getting your friends to downvote, how about suggesting an actually-healthy alternative? Don't complain about downvotes, it makes for boring conversation.
As for the other part of your comment, when I mentioned swimming etc. in the context of overall benefit, not harm to joints. I've yet to see evidence that cycling is easier on the joints, and I've seen plenty that it's slightly below running in terms of aerobic benefit. Sure, an elite cyclist probably has a higher VO2max than I do, but if we compare apples to apples then we'd have to compare to an elite marathon runner and I don't think that comparison would look so good.