Not really, it just has to work on a few people.
With how cheap online ads are, if just 1% of people are stupid enough to act based on ads, it makes them worth it.

With how messy a evacuation this large and sudden tends to be, stopping it may save lives.
It depends on what Israel does after the time is up though, so that isn't for sure better or worse.

The impossibility of evacuating all those people safely is the point, Israel wants the civilians to die.
This is the modern Trail of Tears, but since Israel has been predetermined to be the good guy it will be cheered and celebrated.

From your own source:
"For the 20mph sites (which are not thought to be representative of all 20mph roads), the average speeds were above the speed limit for all vehicle types, ranging from 22mph to 28mph but below the average speeds seen on the 30mph roads."
So the average speed does decrease, increasing safety. Just because the effect isn't a perfect 10 mph reduction doesn't mean that it does nothing.
This means the proposal is effective, but it could be improved with traffic calming measures.

For anyone that doesn't get how incredibly stupid this is, imagine Coca-Cola mandates all its workers to drink Pepsi.

The White House must be angry libs on lemmy then.

With one post you won't get anywhere, you need to put some more effort. I have my own community, which is quite a bit more niche than yours, but by posting everyday it has been growing slowly.
Yours has lots of potential but needs more people to find it. Most people find a community from a post and people tend to look at newer posts, so you have to put something out regularly.

The linked study in the article has many of those, starting at page 20

Turns out forcing people to use Twitter less makes people use Twitter less, what a discovery!

On Reddit I just made a few comments and posts, mostly a lurker.
Here it's completely different, I have my own magazine, where I put the effort of making a post daily, and it actually feels better than lurking.

I'm in the same situation, I've made m/rhythmgames with also 3 subscribers, no responses yet but still better than being on reddit!