1 Timothy 5:13-15 At the same time they also learn to be idle, as they go around from house to house; and not merely idle, but also gossips and busybodies, talking about things not proper to mention. 14 Therefore, I want younger widows to get married, bear children, keep house, and give the enemy no occasion for reproach; 15 for some have already turned aside to follow Satan.
Briefly, that's the whole point of what Paul is trying to prevent by laying down general advice. It is younger widows, generally, not these younger widows only.
It is not realistic to think that everyone can ignore certain provisions for avoiding sin and still avoid the sin they serve to control. Prudence determines that we shall not needlessly add to the severity of any struggle against sin. There is a wide difference between saying "You have an excuse for sexual sin because you are unmarried" and saying "Marriage can be a helpful preventive to fornication." It may be that lack of prudence is not often the root problem; but it is a sufficient aggravating factor in so many areas that it is worthy of being addressed. Obviously a cure for disease depends on addressing the root; but symptoms and side effects sometimes need to be ameliorated immediately as well.
I don't understand your affirmation that nothing external points to a person being called to marriage or not. You've already admitted that certain birth defects might point to them not being called in that way. A lack of need/desire could also point to them not being called. An absence of opportunity would also point to them not being called to that at the moment. So when you have the opposite of those points, when you have an external and an internal suitability conjoined with opportunity, that seems to be a call to marriage as much as desire, gifts, and church confirmation and opportunity verify a call to the ministry.
I was about to start, but you kind of rained on that parade.BTW, thanks all of you for this discussion. It is actually nice to be able to discuss this issue with someone without people engaging in name calling.