Board Thread:Theories and Speculation/@comment-34277398-20180522015234/@comment-4974066-20180522022022

Kurama was under Obito's control via the Sharingan. How that equates to being able to summon him idk. It's said you need a contract to summon a creature and Obito seemed to have one because Minato used the Contract Seal to cancel it. So I guess people are able to summon something if they're under the control of the Sharingan. Iirc, knowledge about the sharingan's ability to control tailed beast isnt that well known and I believe the only reason ppl said that about Madara was because he was the only one who set out to attempt it. However what is well known is Madara's battle against Hashirama where he used Kurama against him. The other Konoha ninja could just be going off of that basis alone.