Minecraft weird?

first: the picture with the Nether background is ok

second: why is there an exclamation mark on my Optifine and NoRisk client?

third: why can I suddenly play with the snapshots?

There was a launcher update.

A look at the changes answers your questions:

Add warnings when starting versions of Minecraft that might not support the latest in-game player safety features
Add "Modded" as a filter option to Java installations
Change background of Minecraft: Java Edition play page (thanks r / Minecraft for the height fixes discussion that brought this to light)

And how do I do that?

They came when the launcher started.
You can't change anything about it.

So now these things stay there forever?!

That's the way it is

What's so bad about that? You can only see it for 2 seconds anyway.

Well okay

Try to re-create the profiles (delete, recreate), this may fix the error. Unfortunately, I don't know whether it will work.

Definitely give it a try.

Beautiful evening!

Which profiles?

E.g. "Optifine", …

So i can't play optifine anymore? It's just really awesome without XD

Of course you can play with Optifine and Co.
At the first start a meaningless message comes up, but you can deactivate this directly. After that everything goes as before.