Ok, I see where you are coming from. However, in the example you used is it really the case that Jack is "heavenly-minded", or something else entirely?
It seems to me that this is a bad choice of words and although one should find out the context of a statement. I think if it is possible, one should try to show how this isn't the best choice of words.
Hope I am not sounding nitpicky, because I am trying to think biblically.
Here are my thoughts on this subject and in reply to your response:
1. I agree that a "bad choice of words" is a valid criticism. If, for example, we substitute "spiritually-minded" for "heavenly-minded", the pejorative connotation might be unwarranted. But, if we understand "heavenly-minded" in the way it is intended, then it would be warranted. How so?
2. Let me illustrate in this way:
* On the one side, there are those who consider themselves to be "holier than thou". They look upon others who don't adhere to their particular scruples (Adiaphora) as 'worldly' or as one man uttered in my presence in reference to nearly everyone else, "rotten sinners". This is the mindset of the Pharisee who most often boasts of how often he/she prays, abstains from alcohol, tobacco, dancing, card playing movies, etc. And, at the same time upbraids and looks down upon those who don't conform themselves to their particular practices and/or beliefs (again on matters of Adiaphora), cf. Lk 18:10-12. Shamefully, many Elders/Pastors must be included in this group. They make a concerted effort to create an appearance
of being more "holy" than all others. Too often they are condescending in their manner and even adopt a disingenuous soft-spoken, overly meek, sickly sweet manner of speaking, which carries over to the manner which they pray when in public. I am sure you know the type. Their hearts are hardened against the 'common man' who struggles against the world, the flesh and the devil, rather than being broken with compassion (cf. Phil 2:1-4 [It is interesting in this passage that Paul uses two different words for "other" in the Greek; others that are similar and others who are different); 1Thess 3:11-13; Jam 2:8]. What is sorely forgotten is what Paul wrote in 1Cor 1:26-29.
* On the other side are those who go even beyond the externals as those above and who have fallen into "navel gazing". They are so concerned about the mortification of sin within themselves, which in itself is not only a good thing but that which is enjoined throughout Scripture, that they effectively remove themselves from being responsible Christians; servants of the King in this world (cf. Matt 5:13-16). They become emotionally and psychologically cloistered from others, even their own family members. Morbid introspection is not only debilitating but sinfully immature; just the opposite of what the person thinks to be holy and spiritually mature. However, what it does share with those in the first group is the tendency to become overly judgmental of others. They are an expression of the old inaccurate caricature of the Puritan which is, Someone who sits in the dark down in the cellar and says to himself, 'I have this distinct feeling that there is someone out there who is having fun!'.
* Lastly, as Chestnutmare commented, the predominant attitude among the majority of professing Christians in our day isn't of being too "heavenly-minded", but rather too "worldly-minded". Not only has this preoccupation with worldly things captured the minds and hearts of the 'sheep', but it has been adopted by the modern church. Assimilation is the popular by-word and their practice. It has lost its first love, assuming it had it in the first place. A yearning to be faithful both to the doctrines of the faith but particularly in its right application, particularly as it pertains to the worship of God and the preaching of the Word. Some have gone the way of exhibiting a 'social gospel' approach, focusing more upon supplying the physical and alleged psychological "needs" of people, forgetting that the people of God are to not be of this world nor to be enamored with the things of this world. The greatest need of fallen man is to be delivered from the bondage of sin and to be reconciled to God in the Lord Jesus Christ.