He asked a question, you answered with a question as well as with your own opinion what is wise in your eyes. It seems he loved N900 and would love to use it again if whatsapp would work. No matter how low the specs are compared todays devices. It is just the love for the device that drives people.

I have a drawer full of smartphones from my favorite era that was 2008 to 2014 so you don’t need to tell me that.
If you work in tech you already know that the newer the phone, computer, whatever, the faster the better.
When nostalgia hits you always remember the fun you had with device X let’s say. You take it out, enjoy it, try to do any simple task and it fails. Then after some time fun becomes frustration and you just shove it back in the drawer until next time.
That’s what I do, that’s what my friends do, that’s what hundreds of collectors that I know do.

In this specific case the guy gave up on the phone and went on android 10 years ago. He remembered the n900, probably though it will be fun to use it with something very basic like WhatsApp that obviously doesn’t work like everything else.
What should I tell him? No it doesn’t work but it’s a great device? He had it, enjoyed it, sold it even when some things where kinda working, so I’m pretty sure he knows that. I’m also pretty sure that if he could afford to have a device just to have it, he wouldn’t ask if anything works, he would just buy one.

And then I see someone ignoring completely all the available new, fast and secure phones/OS’es that you can have today like there’s no other option, and on top of that basically saying that using a n900 today you are secure and private. Since I’ve spent some years in cyber security I find that borderline criminal, not just misleading.

Again, I am not someone that doesn’t like legacy devices. To this day I still keep my first N9 powered on every single day and I still hope that there will be a miracle and I will see a modern version in my lifetime.
I am also totally fine with everyone using whatever they want for a phone. Do you want to use a N900 today as a primary device? Do you know what that means functionality wise? Are you perfectly fine and can afford to use a device like this today? If yes I’m very happy for you and I also envy you.
But the moment someone tries to justify his personal choice with something that is not true or it is partially true, I will comment on that saying my opinion and stating every fact that I know.
That’s it.
No hate, no nothing.

I don't think that hardware feelings or nostalgia is the main perpose to use a N900 in 2023.
The Nokia N900 is something else, it's like a Swiss army knife or Volkswagen Beetle when it comes to smartphones.
The Pinephone gets very close to it.
Elon Musk should buy WA to bring back Yappari on the N900.

I do like the comparison with the PinePhone, it makes sense. I also really liked the concept of the Pine but since it is such an underpowered phone, I chose to buy the best device for every OS I wanted to have. And comparing any OS running on the Pine, i can see that I made the right decision.

I can also see what you mean with the Swiss Army knife and I can explain my perspective in your example.
If I’m in the jungle I prefer to have a machete and If I’m in the mountain I would like to have my shotgun.
The Swiss knife has many functions and it’s great, but won’t help me with a bear or clear a path.

It doesn't have good keyboard and has it good remote control software like Pierogi on N900?

For a hwkb there’s always the Pro1/X.
For Pierogi I really like the traditional Polish recipe! If you mean the IR remote though, I have no clue.
Since every TV etc has apps to use them and remote control them from anywhere, I didn’t really bother with IR since more than 15 years now.

But it doesn't have resistive touch screen, so cannot use stickpen like with MyPaint software with N900.

I don’t know what you mean, but is that a con? I’m talking about resistive screen.
I’m asking because when I moved to Galaxy note 2 in 2012 with Wacom digitizer and 4.000 pressure point s pen, I just wanted to cry from happiness cause I could finally draw properly. Felt like I traveled literally 100 years in the future compared to resistive screens that I always disliked even before capacitive screens.

ok..it has better touch screen than N900...but does it have keyboard shortcuts to tools when painting?

I don’t remember since it’s also an ancient phone.
I’m using one of my iPad Pro’s to draw with the Apple Pencil and either everything is right there for me to select, or double tap the pencil to swap between tools.