I don’t think those assertions rise to the level of “facts”; in some cases they may have some element of truth, or at least they may be perceived that way, and in other cases they are completely false. Anything can be abused; an occasional drink is generally considered harmless for most people, but it would be a serious danger for an alcoholic.
One example: it’s my understanding that some couples use masturbation as part of foreplay. In this case, it enhances intimacy, rather than detracts from it.
Or, how about an elderly widower, who simply misses the intimacy he had during years of marriage? Or a man who’s essentially unmarriageable due to age, physical appearance or disability, or other factors beyond his control? In such cases, these’s no issue of setting unfair sexual standards, and his fantasies might just as likely be about a pleasant dinner date as about wild sex with a Playboy centerfold.
Sure, there are situations where masturbation is unhealthy - or more likely, where it’s a symptom of some unhealthy condition - but there are plenty of others where it’s not. And therefore, it can’t be reasonably condemned as wrong on a “blanket” basis.