[sheept]

It's not that it's unreliable, it's just lazy research. Wikipedia, like all encyclopedias, is a tertiary source, but ideally your essay should be a mix of primary and secondary sources, while Wikipedia discourages original research and prefers only secondary sources. Wikipedia itself recommends against citing it as research[0] for this reason.

[0]: https://en.wikipedia.org/wiki/Wikipedia:Citing_Wikipedia

[kaliqt]

Laziness should never be the issue.

The issue is that Wikipedia can be wrong and you’d only know that by going to the source (or lack thereof), or checking other sources.

[pqtyw]

All secondary sources can be just as wrong, while standards of course might differ being published doesn't prove much on its own. Also of course in many/most non theoretical fields you find plenty of conflicting sources so relying on a "consensus" based high quality encyclopaedia article seems like a more reliable approach if you are new to the field and don't really understand what you are reading.

[bjourne]

Wikipedia and text bots are unreliable sources for the exact same reason---they are anonymous. The point of a citation is stating that "I know this because X told me". The validity of that argument entirely depends on the authority and reputational harm X would suffer for being wrong.