Wikipedia:No trojan horses
Wikipedia has content policies that some editors may find frustrating: an editor may want to put a piece of information in an article, but requirements like WP:Verifiability and WP:NPOV and/or prohibitions like WP:OR and WP:SYNTH might stand in the way. What to do? Sometimes the unacceptable answer may be to try using a Trojan Horse: a fact is wheeled into an article that appears unobjectionable on the outside, but disguises the real, objectionable goal. This is a Trojan Horse, and is an unwelcome editorial act.
A typical Trojan Horse incident involves an editor who would like to make Point A in an article. They can't locate an acceptable published independent secondary source, so they insert Point B, for which there is such a source— and which insinuates Point A. The effect can also be stacked (becoming, presumably, a Trojan Russian doll).
Suppose an editor doesn't like Senator Doe; they want to have the Wikipedia article on Doe indicate that Doe is a hypocrite (the editor's Point A), but the editor knows that doing this outright would violate WP:NPOV, so they find another fact or point that alludes to that conclusion without stating it outright (Point B) and adds a well-sourced reference to the article that in turn points to that (Point A). For example, if Senator Doe is a religious conservative, a Wikipedia editor might seek to show the Senator as a hypocrite (Point A) by adding a real date of birth for the Senator's real child (Point B), which indicates an out-of-wedlock conception and implying that Doe's personal conduct is therefore inconsistent with his views (Point A). The "point", however, is that the date of birth of this particular child has no importance to the article as a whole and appears to serve only to further an unspoken agenda.
A telltale sign of creating such a horse is an editor's insistence on adding and then re-adding some factoid or other that may be well sourced but, taken by itself, is mundane or out of place. For example, that someone grew up in a particular kind of residence (say, a condo) may be too mundane to warrant inclusion in an article about a notable scuba diver and may be legitimately removed from the article on that diver as irrelevant; in addition, if the type of residence being reported is irrelevant to the subject's notability and is also regarded as a rough proxy for some economic status (say, some discussion about the subject having been raised in a council house, a kind of residence that is funded through public money and inhabited by people of lower socio-economic status), the point may be a Trojan Horse.
If, upon removal of such a fragment, the editor who added it to the article replaces it and insists via their edit summary that ("it's true!") in regards to what is clearly a minor point of Schadenfreude, consider the possibility that the point is also a Trojan (which is to say, rather, that it is an Achean soldier inside a horse inside of Troy) and justify your removal of it on those grounds in your own edit summary. Be careful, however, not to place yourself in an edit war with such an editor, and be cautious about removing relevant information from an article on the sole premise that it is a Trojan Horse without being able to support your decision with consistent argument— that is, do not look a gift horse in the mouth unless you are convinced it contains a swarm of Greeks and can show to others that it does!