Are CMS Theme Selling Sites Legit?

Question

Copyright

Good!
There are sites selling nulled CMS themes such as Joomla, WordPress, etc. - is this legal?
They say that since the theme itself is GPL, then by purchasing it and disabling the verification code, they can legally resell it, is this true? And what can threaten buying themes from them (of course they are cheaper but there are no updates)?
Thanks to!
Ps:
The GPL grants recipients of computer programs the following rights, or "freedoms"[6]:

• freedom to run the program for any purpose;
  
• the freedom to study how the program works and modify it (a precondition for this is access to the source code);
  
• freedom to distribute copies of both source and executable code;
  
• the freedom to improve the program and release improvements to the public (a precondition for this is access to the source code).
  

In general, the distributor of a program obtained under the terms of the GPL, or a program based on it, is obliged to provide the recipient with the opportunity to obtain the corresponding source code.
Is it possible to modify? :)

Answer 1

in 98% no, checking the code or any other fraud with breaking the protection is not legal, it may not threaten anything, or it may be shells and backdoors (or other similar infection)