Can we really trust freeware that has no paid version?

So guys, my question personally regards 7zip but it can apply to every other piece of software that's distributed by the developer for free and does not feature a paid version or any other known legit means of profit.
I have this thing installed and now that I need to do some banking I wonder whether I have compromised my system with it. I know there are some fans who will jump up straight to simply assure 'It's safe, don't worry', but let's ponder and reason.

Like, why would some programmer who has invested their time to create a piece of software would share their work totally free without even trying to monetize it? For windows developers, no matter if it's a single individual or a big corporation, the common business model is to release a free version with limited functionality (or just a free trial of the full one) and a paid one. And on mobile platforms it's ads, then in-app paid extra features. These make sense but just giving away?

I looked up 7zip specifically, what can I dig up about it and came across two forum posts
1 and 2 about it being flagged as trojan by AVG, then MBAM. Then others stepped in to insist these must be false positives.

I don't know... Can the dev just be a total altruist and already a millionaire working for the good of humankind? Does anyone know anything about that guy Igor Pavlov?
It's not impossible for a developer to launch a product free of charge and count on exploiting users' systems instead of hoping enough clients show up to pay even a small sum of money over it... And maybe an executable that's manually installed by unsuspecting users (you know, most ppl out there still use admin accounts, in fact I still do, even though I've long heard that I shouldn't - you can spare me a lecture on that, it will go off-topic) will be harder to scan for AV programs than a typical virus that works it's way on it's own in the background.

So I'm interested to see arguments. Shall we really trust even popular freeware without any means of profit shown or stay away from it like fire..?

Right, I know that. I can only wonder how do these ppl then pay their bills...
Actually I've been wondering about Firefox a while ago, but now we know that companies behind browsers can monetize consumer data by selling it to advertising corporations. So browsers are a special category that has it's own business model. But what about the rest of freeware?

Try3 said:

Firefox denies it in Mozilla’s Data Privacy FAQ
How Mozilla Firefox And Google Chrome Make Money makes no such allegation about Firefox.
Denis

I read this through and the key take is that Mozilla's revenue is being paid by Google for putting Google search as default search engine. Alright, this makes sense - at least they don't need to hijack users machines for cryptomining or whatever. Privacy is one thing, that especially concerns browsers, security is something else - universal for all software.
Glad I learned about browsers, then what about rest of freeware though?

- - - Updated - - -

Try3 said:

If you distrust anybody who does anything for nothing then you cannot trust any replies to your question.

Denis

We can distort this into a philosophical discussion but it won't do much good I think.
I guess setting up a piece of software from scratch with elaborate encrypting and decrypting algorithms (or visuals like Gimp that someone mentioned) takes quite a lot more time and effort than dropping a forum reply...

strollin said:

I agree!

Right, a lowest-effort lazy one-word reply can compare to coding encrypto-compressing or graphic editing software. It totally makes sense.