Nirgrantha can mean those who are freed from scriptures. For, it is said:

yada te moha-kalilam buddhir vyatitarisyati |
tada gantasi nirvedam srotavyasya srutasya ca ||

When your intelligence has completely crossed the denseness of illusion, you will be indifferent to all that has been heard and all that will be heard. BG 2.52

Or grantha can mean “knot of false ego.” Thus nirgranthah means “those who are free of the knot of false ego.” It is said bhidyate hrdaya-grantih: the knot of false ego is cut. (SB 1.2.21) Or grantha can mean “bondage.” Thus nirgranthah can mean “those freed from the bondage of rules and prohibitions.” It said cared vidhi-gocarah: he moves about beyond the rules. (SB 11.18.28)

Such persons perform bhakti without seeking results (ahaitukim). Bhakti produces jnana but is superior to jnana. Therefore it is called best or uru. Therefore urukrama means “the Lord who produces the best method, bhakti.”

Can bhakti deliver the liberated? Can the Bhagavatam, a scripture on bhakti, deliver those who have surpassed scriptures? Can a work discussing a server and the served (the Lord) deliver those who have given up all identities of ego? Can the rules of bhakti described in the Bhagavatam deliver those who have given up all rules and prohibitions? To destroy all such protests, the verse says itttam-bhuta-guna: the Lord has such attractive qualities that even atmaramas become attracted. Because of their practice with predominance of bhakti or even just by mercy alone, the Lord gave mercy to the Kumaras, thinking “Let them realize my qualities.” Vyasa gave mercy to Sukadeva, thinking “Let him realize Krsna’s qualities.” The Lord or the devotees may give mercy to some other atmaramas in the same way. Having attained that qualification for realizing the Lord’s qualities, these atmaramas perform unmotivated bhakti. Other atmaramas perform bhakti with the goal of merging into brahman. The word ahaituki cannot be applied to their bhakti. Concerning them it is said:

brahma-bhutah prasannatma na socati na kanksati |
samah sarvesu bhutesu mad-bhaktim labhate param ||
bhaktya mam abhijanati yavan yas casmi tattvatah |
tato mam tattvato jnatva visate tad-anantaram ||

Having attained the state of brahman, being a pure soul, the atmarama does not lament the loss of what he had nor does he desire what he does not have, and looks upon all beings as equal. He then manifests prema-bhakti. Only by bhakti can a person know me as brahman. Then, knowing me as brahman by that bhakti, he merges with me. BG 18.54-55