usage - Function of に and meaning of ものだ in this sentence

The context is : some people are acting stupidly, and someone else watching them says this :

困ったものです。こういう連中には...

My first thought was to translate the sentence in the following way :

That kind of guys are annoying.

With the idea that the speaker is annoyed BY (に) the group and that it's a personal feeling (ものだ).

But the translation I have roughly says :

"That kind of guys should be ashamed."

I know that ものだ can have a meaning close to べきだ, like if we were expecting the action to take place, which would fit with the translation I have. But then I would expect the sentence to end with 連中は and not 連中には for the group to be the subject... Unless there can be a construction of 困る with に, other than "be embarrased by something..." that I'm not aware of...

So, which に/ものだ is it?

Thanks.

Answer

This is all-natural conversational Japanese using anastrophe and a minimal number of words. As I commented above, there is absolutely no ambiguity in the phrase for the native speakers. In turn, it is something J-learners are least likely to say themselves as they simply will not arrive at it if they "translate" from their first language.

「[困]{こま}ったものです。こういう[連中]{れんちゅう}には・・・」＝「こういう連中には困ったものです。」

You will hear the former structure far more often than the latter in real life. The subject is not the unmentioned "I" or "we"; It is the unmentioned "situation" the speaker is in.　 The subject is certainly not 「こういう連中」 as one could tell from the particle choice 「には」 rather than 「は」.

「～～ものです/だ/である」 is a way of expressing (mostly negative) exclamations about something in a non-public manner. The speaker is complaining to himself more than to anyone else; He is not about to go to the court. Note that this has nothing to do with べきだ as OP mentioned.

Another thing that is important is whether one could detect the feeling of "suffering passive" in the phrase. It is there in nuance if not in grammar. In grammar, the phrase is not in passive voice. 「～～には」 tells us what it is that is causing the suffering.

So, no matter how you translate this, it is not going to look like the original in its grammatical structure. Whatever seems fit will naturally be picked.

"I'm really having a hard time with these guys.", "These dudes are giving me a lotta troubles.", "It's a troublesome situation with these guys.", etc.