"After many births and deaths, he who is actually wise surrenders unto Me, knowing Me to be the cause of all causes and all that is. Such a great soul is very rare." Again Krishna uses the word mahatma, great soul. So these are not ordinary boys and girls, our devotees, that you have met, no. They are to be considered as actually wise, great souls, because they have experienced in so many births the miserable disease of material life and they have become disgusted. Therefore they are seeking higher knowledge, something better, and when they find Krishna and surrender unto Him, they become mahatma, actually in knowledge. This material world is just like a prison-house, a punishing place just to bring us to that point of becoming disgusted and surrendering at last to Krishna, going back to my original mature of eternal life of bliss and complete knowledge. So these devotees, that is their credit, they have done what is "very rare" amongst all men in the human society, sudurlabhah, very rare.
So after surrendering to Krishna, that will be the final receptable for investing his love: in God. If somehow or other anyone develops their dormant love of God—love of god is present there in everyone, just like fire is there in the unlit match, covered-over—if Krishna becomes the Supreme Adorable Objectality, the Supreme Friend, the Supreme Master, the Supreme Lover—then, oh, he shall never again become disappointed or unhappy. Rather, because his loving propensity is rightfully placed,
mac-citta mad-gata-prana, bodhayantah parasparamkathayantas ca mam nityam, tusyanti ca ramanti ca(BG 10.9)
the devotee, one whose life is surrendered to Krishna, is always enjoying "great satisfaction and bliss" and he is constantly "enlightened", always positive, not negative as you say. The advanced devotee is the friend of everyone: yoga-yukto visuddhatma, purified soul engaged in loving devotional service to Krishna, sarvabhutatmabhutatma, he is dear to everyone and everyone is dear to him; and in another place Krishna claims that: yo mad bhakta sa me priya, that His devotee who is very dear to Him, advesta sarva-bhutanam, maitah karuna eva ca, is not envious but is the kind friend to all living entities. The devotee is supposed to be, furthermore, equal to everyone, panditah sama-darsinah (BG 5.18), never discriminating; this one good, this one bad, no.
So these are the descriptions of the more advanced stages of Krishna Consciousness devotees, when has got mature knowledge by development, and at present many of our students are young boys, they are learning gradually and the process is so effective, certain, and authorized that if they stick to it they will come to the right point, as you say, of loving. But that love is not material, that is our point, so it may not be judged on the on the false sentimental platform of ordinary mundane dealings. So to say they are not loving, that maybe true from the materialists point of view—they have given up affection for family, friends, wife, country, race, like that, all based upon the bodily concept of life or flickering sense-gratification—they have become little detached from Maya's love, or lust, and they want Krishna's love, or endless, full, rewarding love, but they have not yet developed to that point, that's all and we cannot expect that all of a sudden, being addicted to so many bad habits, your countrymen, will give up eating flesh, taking intoxication, sex-life, and so many other nasty things, and become overnight great self-realized souls. That is not possible. That is utopian. Just becoming initiated as Krishna's devotee puts him in the topmost category of human society: sa buddhiman manusyesu, sa yuktah krtsna-karma-krt: (BG 4.18) "he is intelligent among human society, he is in the transcendental position, although engaged in sorts of activities". And such devotee, no matter he has not advanced yet to the highest level of spiritual understanding, still he is to be considered the most exalted personality never mind he has got any temporary frailties:
api cet suduracaro, bhajate mam ananya-bhaksadhur eva sa mantavyah, samyag vyavasito hi sah(BG 9.30)
"Even if a devotee commits the most abominable actions, he is to be considered saintly because he is properly situated,". As you will say, "To err is human", so in the neophyte stage we may always expect some discrepancies are there. Kindly see the things in this light and forgive their small mistakes. The big thing is they have given their life, everything to Krishna—that is never a mistake.