Yes, a single Christian man can be respectable, prudent, hospitable and above reproach, etc. But he cannot, being single, be the husband of one wife, nor in such a state can he have his children under control (except he's a widower), demonstrating thereby his capacity to rule well his own household (and thus, by extension, the church).
I've known short fellows who could handle a basketball with incredible skill, dribbling circles around everybody, sinking 3-pointers consistently from the top of the key, passing brilliantly, reading the flow of play with great skill, and so on. But they were short. Too short. When it came to playing among guys nearly twice their height and weight who, though not as adept with the basketball as they were, still had above average ability, these short fellows found their athletic advantages completely nullified. Yes, they were great ball-handlers; yes, they were great 3-point shooters; yes, they could pass skillfully; yes, they were great court readers; but they were too short.
In the same way, it doesn't follow that because a single man is kept from the Elder role because of his singleness, he isn't therefore a spiritually-mature and hospitable person, able to teach well, etc.. Being married with kids teaches a man some very important things about himself and walking with God that a single man just can't learn as a bachelor. Most crucially, a man's family becomes a "mirror" of sorts in which he sees an often very unflattering reflection of himself as they test him constantly in the areas of selflessness, wisdom, spiritual leadership, and consistency (among other things). A bachelor does not have the benefit of the tempering, the refining and revealing influence, of a wife and children. As a result, he lacks experience and self-awareness that are crucial in the role of an Elder. But, again, this isn't to say he is, therefore, not at all prudent, or hospitable, or above reproach, etc.
But I didn't. You are arguing here against a Strawman assumption you've made, not my actual words.
Of course, the Holy Spirit can mature a man spiritually. But the Holy Spirit simply cannot give the single man the experiences of a married man who has navigated the intimacy and relational complexity of marriage and the many challenges unique to raising children.
I didn't marry 'til I was 39. To that point, I had been involved in many Christian ministries, teaching and leading youth, and preaching, and discipling men. I was no "novice" to the faith, that's for sure, my spiritual maturity recognized and called upon by various churches and individuals. But, man, marriage revealed things about me to which I was totally oblivious, led and matured by the Spirit though I believed I had been. Goodness! The "mirror" my wife was to me revealed a man who had some serious growing yet to do spiritually. Her relational intimacy with me, her proximity to me unique to the marriage relationship, was able to expose areas needing growth that could only have been revealed by such a relationship.
Anyway, only a single guy would assert that he can equal the spiritual growth of a married man. All married men know the silliness of this thinking.
Strawman.
It's amazing how you've talked yourself into believing I have a view that you imposed on me! The Strawman you've constructed is your construct, not mine.