It's not the only case of easy stories turned hard because use of computer (the spanish version is worse, it uses a calculator), either. 童　わらべ　"juvenile" (#436) shows a person that "stands on the house of his fathers, because it's too young to buy one". All stories using that primitive improve by using this meaning, which is common sense, because chinese created the kanjis in a way not very different to the one we use to learn them: by creating stories featuring those elements. That's why using arbitrary meanings to relate them only messes up the stories.

The original form of 童 derives from 重 and another component that's not a kanji by itself.  It has nothing to do with 立 or 里.  So remembering it with a mnemonic that uses the house of his fathers is just as "innacurate" as one that uses a computer.  In fact, it's worse because you seem to be fooling yourself into thinking you're learning historically accurate information.

Many of the characters have been simplified over time, so that you can't tell just by looking at them what components they were formed from.  Traditional Chinese writes 臭 with 犬 where Japanese uses 大, so anyone who thinks they're being more accurate with a mnemonic involving "big" instead of "St. Bernard" is doing just the opposite.

Just chill out.  Mr. Heisig knows what he's doing.