ワードプロセッサー is defined as a computer system capable of inputing, displaying, editing, saving, and printing text. This used to refer to dedicated word processing appliances, but from around the late 90s changed to refer to word processing software for personal computers which became more popular.[1][2][3]
The ワープロ馬鹿 phenomenon stems from IMEs automagically converting romaji/hiragana to kanji, and this is most commonly seen during use of word processors like Microsoft Word.[4]
[1]: https://www.weblio.jp/content/%E3%83%AF%E3%83%BC%E3%83%89%E3...
[2]: https://kotobank.jp/word/%E3%83%AF%E3%83%BC%E3%83%97%E3%83%A...
[3]: https://gogen-yurai.jp/word-processor/
[4]: https://ejje.weblio.jp/content/%E3%83%AF%E3%83%BC%E3%83%97%E...