We can only speculate about the meaning to/intent of whoever drew it. The reality is that regardless of intent or personal interpretation, if anyone in the workplace recognizes those images as having that kind of meaning and is made uncomfortable by it, that constitutes workplace harassment, whether it’s intentional or not. If the company doesn’t take it seriously, they will be liable for legal action. At least in the US - I assume most other English-speaking countries have similar laws. So it’s not really an overreaction - they need to protect themselves as much as their employees.

Whether you or I ascribe that meaning to the images or not is immaterial - clearly, someone does. Given that the images have nothing to do with work anyway, the only thing that matters is whether they genuinely bother people.