"Then, you look closer and that's not cute. That's not right."
Mr Pocock realised the image showed the outline of a person hanging in a scene that looked "more like a lynching".
"Any hatred towards any race or any person is just extremely unacceptable, especially for a large establishment like McDonald's," Mr Pocock told 7 News Boston.
Others were shocked over the placement of the decal, which is in eye level of most children.
"McDonald's represents Ronald McDonald, helping children," one woman said. "Across the street from a high school, it's just wrong."
Mr Pocock told the news station it was "insensitive" and they should have thought twice about putting it up.
The McDonald's restaurant owner and operator Chuck Lietz has since apologised and removed the image, saying they "deeply regret that these decorations were on display".
"As soon as we identified the inappropriate content, we immediately removed the decorations display," he told 7 News Boston in a statement.
"Creating an environment that is welcoming and inclusive to all our guests and employees is critically important to us, and we apologise for any unintended offence they may have had on our community."
WHERE TO GET HELP:
If you are worried about your or someone else's mental health, the best place to get help is your GP or local mental health provider. However, if you or someone else is in danger or endangering others, call police immediately on 111.
OR IF YOU NEED TO TALK TO SOMEONE ELSE:
• LIFELINE: 0800 543 354 or 09 5222 999 within Auckland (available 24/7)
• SUICIDE CRISIS HELPLINE: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• YOUTHLINE: 0800 376 633 ,free text 234 or email talk@youthline.co.nz or online chat.
• NEED TO TALK? Free call or text 1737 (available 24/7)
• KIDSLINE: 0800 543 754 (available 24/7)
• WHATSUP: 0800 942 8787 (1pm to 11pm)
• DEPRESSION HELPLINE: 0800 111 757
• SAMARITANS – 0800 726 666.