Bomes is a weird insane bombpost thing that occurred on 4chan's history & humanities board, /his/.
/his/ is well known for being a friendlier /pol/ version. It talks about history and humanities, many believe this is a neo-nazi board, that's not the case though, /pol/ while supporting nazis, /his/ dislikes nazis and many browsers of /his/ tell '/pol/tards' to go back to their own board. /pol/lacks browse /his/ more often than any other SFW board. That proves that /his/ is an easy target by /pol/ due to the sheer amount of social science, which has something to do with Nazism, /pol/tards' most common idealogy.
There aren't a lot of questions surrounding the holocaust in /his/ as /his/ is no stranger to the holocaust and most of its users, unlike /pol/ (Whom are Holocaust deniers), /his/ believe in the Holocaust. The problem is that this makes /his/ easy target by /pol/tards' that there will be a holocaust thread, holocaust denial specifically. Many of course wanted evidence of the Holocaust and so on, nothing special…
But the match first lit on March 19th, 2020 when a user of /his/ made a thread asking for 'evidence' of the Holocaust, specifically, 'forensic evidence'. Many users showed him photos of bodies and shoes. That wasn't enough for him, so he wanted something more, like 'bones'. Since this is 4chan, they will dumb down the word, like MOAR (More) or SAUCE (Source). So they instead called it 'bomes' to mock OP, when OP kept asking for bones, many decided to give evidence for such (Which he believes has been forged/faked), others decided to other stuff, mock OP's logic 'Give me every bome of WWII soldiers or there weren't many kills' or mock OP's 4chan status,

like his 'Reddit spacing' which

is spacing posts in this

way which anons

really hate,

or his neckbeardness and how he acts.

It got popular, many users of /his/ kept using the joke anytime someone referenced a historical thing, like soldiers or any dead body, they would often ask for 'Bomes'. There would often be threads dedicated to the 'Bomes' meme. /pol/ saw such act as disgrace to them, so they decided to lunch a huge raid on /his/, which was quickly gone by an hour. It also saw a large amount Holocaust Denial threads, many now asking for Bomes (Instead of the usual arguments against the Holocaust truthfulness).

In short, the bomes meme was started by an anonymous user wanting to some 'forensic evidence' of the Holocaust, this turned into a massive debate as he refused bodies or shoes, all he wanted were bomes (Bones). So anytime there will be a thread about any type of history, most of /his/fags would often ask for bomes; just to mock the one who created the meme and other Holocaust Deniers who use such arguments.