In some cases, notably the unwanted and/or coerced/cajoled activities, lifelong mental scarring is ignited by a "sexual" attack. There is also the possibility of a younger participant feeling coerced into something they dislike, because of the adult's abusive authority. This is not in any way specific to sexuality and has more to do with sexual attitudes, mores and unhealthy authority relationships. Subsequent memories can also be exacerbated by the long-lasting memory of an experience that an individual is repeatedly told to view as dirty, shameful and profound. Understandably, this can easily lead to mental disturbances and depression.
None of this implies that any form of willing physical contact/pleasure has a high capacity for harm, let alone life-long mental scarring. You could even say that what we are seeing is a social construct of abuse trauma fulfilling its own prophecy in the minds of its victims, or at the very least exacerbating fundamentally harmful abuse. This is something that any good-meaning victim advocate should be minded to investigate the possibility of, since we know from studies that the perception of ones own experiences as abusive or non-abusive is a major modifier of outcome. From this, we can conclude that changes in broader social perceptions and the promotion of youth agency over traditional authority relationships will reduce the prevalence of negative outcomes.
If a personal perspective of abuse is indicated
One way of overcoming bad memories, may be to challenge the sex - negative foundations upon which the value judgments and feelings of shame are based. No one needs to associate their pain with their sexual history when the perceived "sexual acts" (even if coercive) are a passive vector of society's guilt. As any fair-minded therapist would tell you, that would be doing yourself a disservice and encouraging forms of neurosis that may make present relationships impossible. Therapists who encourage clients to see themselves through a sex-stigma lens as perpetual victims are probably unprincipled hacks who are on the grift.
"Adaptive" argument
Trauma is an evolutionary adaptation against underage sex
In this case, why would the trauma delay its onset by 5-10 or more years, as famously claimed by victimologists every time they encounter data concerning harmless voluntary sex between minors and adults? When a dog bites you, or you hit yourself on a rock, the pain response (and disincentive) is immediate. However, when we look at the data concerning CSA, it appears that whenever researchers push the recall widow out yet further, there is no evidence of delayed trauma. And this remains the case by the end of life as well.[1]
We should also question how this "disincentive response" appears to have evolved in the relatively short period (2 centuries, and a few generations) in which anti-sex attitudes concerning youth have become widespread in some societies. If this is in fact a longer-term genetic trend, how did all the great civilizations routinely practicing/institutionalizing these acts even survive to prosper and defeat other civilizations?
The evolutionary argument appears to be a rationalization of antisexualism.
Excerpt Graphic Library
The EGL on Harm has some relevant information. Just right click/save and reproduce by uploading in short-form media to bypass character limits.
Basic Rind Paradox infographic
Summarized Rind findings
Rind and Tromovitch (2000) on Iatrogenic Harm
Research pointing to no intrinsic harm profiled in The Guardian
What victimologists say about youth perception + admissions of iatrogenic harm
Self-perception: Importance
Some reading on secondary harm and perception/situational variables
More secondary harms
Intrinsic vs secondary harm
Daly's 2021 repetition of Rind (1998), finds that self-perception is far more important that abuse status
Lahtinen Report: Most common reason for not reporting - event not serious enough
Finer analysis of Finnish Victimization Survey (Rind)
General reading on intrinsic harm
Oellerich on the self-fulfilling prophecy of iatrogenic harm
Oellerich comments further on iatrogenic harm
CSA harm was known to be confounded even before Rind
No "typical" CSA reaction or "syndrome"
Rind on methodological issues/limitations of victimology
The Lanning (1992) report - full of hysterical conjecture, nevertheless describes the "most common" forms of offender and victim in banal terms that are applicable to most relationships (in order to prepare investigators to pathologize banality)
Percy Foundation review of Chloe Taylor: "Foucault, Feminism, & Sex Crimes"
2022 debate response
Illinois state investigation finds a "pedophile" was his victims' "best friend"