Being able to kill children would cause much controversy that Bethesda wants to avoid. In their other games, like Fallout, the option to kill children was also not available. This is a statement released from one of the developers of Fallout. You can apply the context to Skyrim as well:
"We do not want to cross lines like killing kids (we actually never got as far as even putting kill-able kids in any builds of the game). For us, that was certainly a line we did not want to cross, and we think that was the right decision."
Being able to kill children could be viewed as inhumane and cause an uprising from certain groups of people. That is just one of many reasons why it would not be smart to have such an option. Also- the official forum is, of course, more strict in ways. They probably do not want the topic of killing children floating around because the topic is controversial in itself and could cause a number of problems. There are more reasons than you might think of why they would delete such a topic. We're viewing it from a player and consumer's point of view, they're viewing it from a business point of view where their reputation is always at stake.
I'm not saying that deletion of topics is always fair, I'm just trying to explain why they
might have done it.
