I think you must have been wrong ... since 2013 there are many scripts, bot, tool, etc... monitoring transactions 24/7 trying to find reused r values and other possible vulnerabilities to drain wallets https://bitcointalk.org/index.php?topic=271486.0/

But if you want to learn how to calculate reused r values ... I'll show you in the simplest way possible.

Modular calculation with this p:115792089237316195423570985008687907852837564279074904382605163141518161494337

(z1-z2) / (s1-s2) = the result will be the k value

Now calculate this:

(s * k) - h) / r) = Private key

DONE!