We all complain about not getting answers when applying, but here is what I have observed (repeatedly).

When you apply to companies, you get an answer in 80% of the cases. It may be a negative answer, and with no useful data telling you why you were not selected, but it is an answer.

When you apply to recruiting companies, you rarely get an answer. The reason for that may be that they may not have the role exclusively (or not at all). Don't just assume that they're bad, heartless, emotionless people; they may just not be authorized to reject you at all!

Of course, they could go on and tell you one of the two things: "we didn't submit you" or "we submitted you but you weren't selected".
Having this information, one might try or not to approach the company through alternative channels. Not having this information is baffling.

Whenever I see jobs I like, posted by recruiting companies, I try to find out which is the real company with that opening, and if they have this job advertised, I apply to the company directly.

Which is not so difficult, considering how lazy some people are in transforming the job description to a job post; usually and for the not so professionals, just a copy / paste activity.