Almost in the sense of against sexuality in general? Many act like that it is ok to have SEXUALITY if you are legally married, otherwise not only to them, should one not have sexual intercourse, but one should also be completely sexless. Biologically and psychologically this is impossible, so one must PRETEND to be asexual instead of ACTUALLY being asexual, IF one wants to please these kinds of Christians. Now granted, many Christians are much more sex positive in general, but there are groups who are more extreme.
Many ACT like that if you are single AND you have sexual thoughts or feelings AT all, you are violating Matthew 5:27-28. Herein lies the dilemma. Because of how our bodies and minds are designed, this is impossible except for a select minority of the human population.
I have discovered a few things that may partially solve this dilemma. First of all, the Old Testament was originally written in Hebrew and some Aramaic, and at about 270 B.C. a Greek translation of it was made, called the Greek Septuagint. The New Testament was originally written in Greek. Also, one of the major rules of biblical interpretation is to use context. It is to use the verse surrounding a word, the verses surrounding a verse, chapters around a chapter, a book of the bible around chapters, and see how books of the bible fit together. I contend also the historical background of the ancient world, and also the Apocryphal literature that gives more details on events in the bible.
In breaking down Matthew 5:27-28, I noticed that Jesus is talking about ADULTERY of the heart. So the key here, I believe is that Jesus is saying that DESIRING to commit adultery IS ADULTERY of the heart. In the Old Testament adultery is defined as taking another man's wife or betrothed (in the ancient world you needed an official divorce so break a betrothal, so that counted as adultery). In an Apocryphal book taking another man's CONCUBINE seems to be a "lesser" form of adultery with a lesser punishment than prescribed in the bible for full blown adultery.
Second, the base Greek word for woman is "gune", and a different form of the word is used in Matthew here "gunaika" which is a suffix added on, and when I went to check a list of verses using "guinaka" and "gune", most of the time "gunaika" is used when referring to a wife, "gune" is a more generic term for woman. This isn't ALWAYS the case in the New Testament, but it is a general pattern. So then we have ADULTERY of the heart, and a form of the Greek word for woman that usually refers to a wife. Contextually it would make more sense Jesus is referring to a wife here, and not a single woman. Also the Greek word for lust means to desire or a strong desire. In the Greek Septuagint when talking about coveting another man's wife, it uses the same Greek word for lust that Matthew 5:27-28 uses. In fact I believe it is likely Jesus was MERELY reminding the people "you know what, you know physically adultery is a sin, but SO is coveting another man's wife". I believe Jesus was merely reminding people of the commandment against coveting your neighbor's wife here.
This harmonizes also with Old Testament passages where some characters had concubines in addition to wives or even instead of a wife or wives, and they were NEVER told to repent or marry their concubines.
Those wonderful, devout, religious people known as the Pharisees, so devout that they practiced their religion all the way to....HELL....taught that only outward behavior counted, your heart didn't matter. With this in mind it is no surprise that Jesus corrected these misconceptions when He came along. The Pharisees were such nice fellows, they said your heart didn't matter, but then they added thousands of rules to the commands in the Law of Moses. There are some verses where Jesus accused the Pharisees of teaching the commands of men as if they were the commands of God. This is what He was talking about. I don't exactly think Jesus was displeased when the Pharisees told people to do things ACTUALLY in the Law of Moses, he just called them out for the totality of their hypocrisy.
This makes much more sense then in that people need not feel guilty over having sexual thoughts or feelings if they are married. The legal marriage and divorce system in the US is a mess, but I won't go into that here.
I have heard a few Christian teachers LITERALLY say that for single people that ANY sexual thought or feeling, ANY AT ALL, is a violation of Matthew 5:27-28. In my own experience, and probably for most people in the world, in order to stop having sexual thoughts and feelings, you would need to leave your body. I do wonder if sometimes a spiritual union is a parallel of a sexual union in the natural (there are actually few bible verses that hint at this), so even if you leave your body, you might get the equivalent anyway. This may or may not produce the same kind of feelings as sexual pleasure, at least not all the time. from Ephesians 5:
31 “For this reason a man will leave his father and mother and be united to his wife, and the two will become one flesh.”[c] 32 This is a profound mystery—but I am talking about Christ and the church
At the very least a sexual union SYMBOLIZES a spiritual union, so churches had better be careful not denigrate sexuality too much. The bible does list the sexual sins, including adultery, incest, rape, animals, and things like that, but again because those things are a twisting of sexuality. Maybe ACTUAL sexual sin is a big deal to God BECAUSE sexuality symbolizes a spiritual union.