Richardson watched Hatfield's strike - which was ruled out for offside in the 86th minute - and felt the officials made the wrong decision in Saturday's clash at the Crown Ground.
"He wasn't just onside, he was miles onside," said Richardson, whose side are unbeaten in three. "It was embarrassing and a few decisions like that have happened to us this season and they add up. These could prove costly for us and can affect people's lives.
"The decision is not even close and I have had a brief word with the officials after the game and they believe they are 100% right. I would like to hear their explanation when they have seen it again.
"We have done enough to win the game but there are still positives to take - like back-to-back clean sheets and that the lads have come together in the last few games. If we stick together we will climb the table."
Richardson, whose side are one place and one point above the drop zone in League Two, is keen to boost his squad after on-loan defender Mark Hughes was ruled out for the rest of the season with a calf injury.