Let me give you the following information:
If it is not your own room you are playing in and you somehow get the host, you should assume that the room you are in follows the unspoken rule of host rotation. That means that you give the host to the next player after you picked 1 map and finished playing it.
Multiroom management is not osu!'s forte which means that in order for this to work out, everyone is required to collaborate. Unless certain requirements are met, even the room owner can't take the host back from you! If you get host in a room and just keep picking maps without passing on host, this can easily be considered uncollaborative or even rude if host rotation was going on for hours. People leaving together to make a separate room is an absolute legitimate thing to do if that was indeed the situation.
Furthermore the quotes you gave are not indicating in any way that you were treated like "absolute, utter shit". These people are not entitled to follow your lead and if they asked for host and you didn't give it to them you indeed "don't care about the community" in one or the other way. You didn't get insulted in any way from what I can see so your interpretation is arguably quite a bit off. Referring to your rank might be a bit unseemly but it's simply more likely for unexperienced players to not be acquainted with host rotation and should not be confused with actually bashing on newbies.
Last but not least a small trick that will "hide" your rank in multiplayer:
Other gamemodes, especially Catch the Beat and Taiko have rather lower player population which means that you can rank up to ~100k with very little time investment.
If you set your gamemode to another gamemode in your singleplayer song selection and join a multiplayer for standard mode, your rank from the other gamemode will be shown for others next to your name like this:
As you can see at the top and next to my name my CtB rank is displayed although the selected map is standard mode (cause it has the 1 in a circle as icon, not an apple). People will still be able to find out your real rank for the game mode by right clicking on your nickname but it's not immediately visible.