VeraCrypt a weak point Biggest flaw in VeraCrypt(or other Encryption programs)  is Hash Algorithm. 
VeraCrypt hashes (SHA,Whirlpool,Streebog) it is the only point where can break an encrypted disk. Because break algorithm (AES,Towish,Camellia,Serpent,Kuznyechik) it is practically impossible. 
VeraCrypt hashes can be broken by Police with the appropriate cash input. Hashcat can break VeraCrypt hashes. 

How to protect against it? 
Will longer mouse movements help?
And hashes are really so dangerous? 

I invite to the discussion.
VeraCrypt hashes can be broken by Police with the appropriate cash input. Hashcat can break VeraCrypt hashes.


Breaking a hash algorithm and brute-forcing a hash input are 2 completely different attacks. Veracrypt uses PBKDF2 with half a million iterations for volume containers, which is an appropriate amount. The weak point which allows recovery of a Veracrypt volume is the strength of the password


  How to protect against it?


Use better passwords and keyfiles, and use a bigger iteration count (PIM)


  Will longer mouse movements help?


No, that has little to do with the password hash strength


  And hashes are really so dangerous?


No, poor choices of passwords and bad opsec are dangerous, it is easier to install hidden cameras and observe keyboard input, or to use torture