To be fair, "sharing" is one of those things which is a natural thing people like to do when they have found something meaningful for themselves they are excited about. I certainly would love to share what I've been discovering for myself through qigong practice and the tajii form, for instance. Or, finding a great camera I'm excited about. "It's the best!", beams the enthusiasm of a the inner child. I think that's a natural and healthy thing.
However.... the problem is when that is exploited by a religious system to get its members to "get excited about Jesus," or whom or whatever, and "share" it with others because they a promised the rewards of recognition for bringing people into the fold. Now sharing is no longer about natural excitement alone, but it becomes attached to a mission statement, a duty, a responsibility, etc.
It becomes infected with some ulterior motive assigned to it, and it makes it about personal reward, being seen as a "good warrior of the faith", a notch in their bible belt for saving a lost soul, and all that. It's like selling an expensive vacuum cleaner to them, and you get recognition for it. In other words it taints and pollutes genuine, natural love, with selfish motivation. It isn't about genuine sharing anymore, it has personal ego needs attached to it.
Like you, I find this distasteful. Not only for the person this "love" is being shared with, as it views them as an object to exploit, but for the naive spiritual aspirant who does have a genuine enthusiasm, but is told they need to use that to win souls to their religion. It diminishes their own spiritual truth they are finding for themselves. It taints it. It's a like a leech attached to your face as you try to smile to the person you're talking with. People can sense something is off, and so can they about themselves as they try to "share" as some sort of religious obligation.
It's my hope for anyone caught in this religious obligation to "share the faith", that they will realize how that is not truly spiritual rewarding, but that just sincere and authentic love without strings attached, without a compulsion to attach religious teacher's quotations to it to promote a system of belief, is the actual point of any spiritual path. To be genuine. To be that innocent child who is excited about this wonderful new thing they have found that brings them happiness. It should be about their happiness, not the thing they found their own happiness through at that time.