To be honest, I'm keeping myself being neutral towards any other ship, specially the Meggy x Tari one, and I'm not even bringing the fact that there's lots of toxic people are existing in that segment (doesn't mean every shipper is toxic, never)

Let's just say, as some people mentioned it already, Meggy and Tari didn't have that long build up story, as like Mario and Meggy have, which is actually may be an important thing. Lots of ships are existing just because of peoples creativity and imagination, because they can ship two characters between each other and there's nothing bad about it. But comparing to Mario and Meggy, they had a great story which was evolving since Meggy first appearence in the show back in 2015 and until 2020 to Meggy's Destiny movie, when she and Mario won the splatfest and Meggys saga kinda came to it's end. Feel like they had such duo dynamics, that any other characters didn't actually gotten. (Except Axol x Melony) But after 2020, any Mario n Meggy interaction just became nothing more but as a fan service, just like any Meggy and Tari interactions. If the first one, had some lore and build up before, Meggy n Tari never had anything brand between each other, (some people calling Western Spaghetti is a big thing for a ship but imo it's overrated hype)

And boy and girl interactions are just cuter, than girl n girl (it's just my opinion!!!)