Is this sentence correctly constructed?

I'm psychologically victimised by two humans’ sexual activity witnessed unintentionally outside the windows of Block E, HFC, where such practice is prohibited.

And has the author clearly expressed himself?

<<And has the author clearly expressed himself? >>

In conetxt, probably. We don't know what HFC or Block E are, of course.

It's *almost* like those ambiguous sentences: it seems to go on longer than it should: "...activity witnessed..." Probably better to say "that I witnessed", to make it easier to read. However, the sentence in itself is quite clear.

It reminds me of some of the sentences I saw when editing for my University’s Press—overly ornate and constructed to seem more intellectual. The person is either purposefully writing in this way for effect (to perhaps dehumanize the character) or needs to read White's "Elements of Style".

I'd recommend "I've been victimised" rather than "I'm victimised"

It is correct, and sounds flowing.

That is it Caspian is either an idiot or a troll.

Excuse me? There's no need to be insulting. What on Earth is a troll when it's at home?

Sorry, Caspian. I thought you were just trying to get a rise out of someone by your comment. I can't agree with you that the sentance is flowing.

My two cents:

From a mere grammatical perspective, the sentence is perfectly acceptable.

Having said that, it nevertheless reads awkward. Too mechanically-constructed.

The author of the sentence is trying to pack too densely the information they are trying to convey.

Here are a couple of alternatives:

_I've been psychologically victimised by unintentionally witnessing two humans’ sexual activity outside the windows of Block E, HFC. Such practice is prohibited there._

_I unintentionally witnessed two humans’ sexual activity outside the windows of Block E, HFC, where such practice is prohibited. I feel like I've been psychologically victimised by the experience._

You don't need to force a lot of information into a relatively short sentence to express yourself clearly. Sometimes a looser style of packing information is going to read much more natural.

Trying to pack information too densely is one of the most typical errors of non-native speakers.

By the way, even if I know more or less nothing of the context in which the incident described should be placed, I find the word "victimised" somewhat ill-chosen. What about "traumatised"?

With all the good wishes,

Achab