jungle is just hard to traverse, and it not as useful for gamemodes like factions or creative due to the amount of work required to take down structures generated in the biome. its not that it isnt a cool biome, its just that it gets annoying to deal with.
Jungles have are quite thick and thus not ideal for building. In survival mode, the larger trees are more difficult to collect wood from than oak or birch trees, and they're harder to farm in. I do love jungles though.
Honestly I really like Jungles biomes there's pandas, bamboo, and the trees make for amazing treehouses! But it does feel unloved by the community AND Mojang. There have been very little updates (besides 1.20 adding a good use for bamboo) that have actually changed/made it a better biome! The (1) structure is not great, the trees are harder to chop down, the docile mobs are eh, and don't get me started on the mob spawning, ALSO no villagers can spawn there! :(
The jungle had its glory day when minecraft as a whole was less fleshed out and interesting. It was The New Thing and a more densely vegetated area than anywhere else at the time really, so it just provided some much needed visual appeal. + The bright green was just eye catching, and added cats (well ocelots). Now so much interesting content has been added for other & new biomes it's just not special anymore, but it has potential. Maybe future updates will do it justice and more people will proclaim it as their favorite? Maybe something biome unique, kind of like blue azaleas for swamps or something. Maybe in future updates the sniffers will be fleshed out to find like different ancient seeds by biome, and since jungles are so biodiverse, it could have like the "coolest" one? Of course that's at the whim of mojang/microsoft. OGs remember when jungles were the real deal. They might be due for a revival. Maybe something could make cocoa more functionally useful? It's not personally my #1 favorite biome (sorry, I've fallen into the cherry blossom trend, it's just too gorgeous, and the bees! Abundant bees!) but I've always loved the bright colors and interesting complexity. Very visually appealing. Jungle wood is also not really an "extreme" color, like birch or dark oak or cherry, so maybe it's just likelier to get overlooked. But I'd wager a guess that there's more in store for the jungle biome that might net some converts, don't lose hope!
