I take it to mean that the car is, at the very least, quite a dark colour.
Now,m if you can show me that someone would say that in regards to my car (which is light blue), then you'd have a point.
It doesn't matter if the car is a dark color or not. To the person saying it, they believed it was black. The same as a light blue car. But let's make it clearer. What do you think happens in court when a person is asked what color the car was. If they say I think it was black they are crossed examined. The lawyer will ask "you think it was black or it was black". That is how different the two statements are and that is how most people understand it.
But let's apply it to something definite like a car itself. There is a big difference in saying "it was a car" to "I think it was a car. The first is a statement of fact. You are saying it was a car and there are no two ways about it. The second is projecting doubt that it could be something else, you're not sure.
By your logic, I should tell my husband he is wrong when he says, "I'm going to have toast for breakfast instead of cereal," since anything could happen on the way out to the kitchen to stop him from having toast. I'll tell him that he really should be saying, "I think I'll have toast for breakfast," instead, and instruct him on the proper use of the English language as determined by Steve.
More quibbling.
Funny enough that is what happens with subjective morality. Morals are equated with "likes and dislike" in tastes for food. So applying it to the hitting scenario it would be like you saying to your husband " you are right for choosing toast instead of cereal". That is a fact statement by you. As compared to saying " I think you are right for having toast instead of cereal". That is an opinion statement.
You are expressing "you think it is right" and not "it is right". An opinion attaches the personal opinion, feelings, or belief to what is being said. In this case "I think" so it is about what "you think" rather than an independent fact that "it is" like that which makes it a personal statement IE "it is a car" as opposed to " I think it is a car".
Fact, Opinion, False Claim, or Untested Claim?
Opinion
Let’s begin with opinion. An opinion is a self-report of feelings or personal judgment, e.g., I’m thirsty. Opinions often contain clue words pointing to oneself, e.g., I think, I believe, I feel, in my opinion.
Fact
The definition of fact is a fact because that’s how knowledgeable English speakers agree to use the term. Definitions are analytical facts, verified by linguistic usage, not by observation.
Fact, Opinion, False Claim, or Untested Claim? – Bruce Murray, College of Education
In other words when a person says something is right or wrong as a fact they are qualifying it by the language they use IE "It is wrong" or " It is right". We shouldn't have to change the meaning of the language used because it doesn't support what you believe.
In this case, the quibbling is important as it differentiates between an opinion and a statement of truth or fact, and when it comes to either subjective or objective moral positions that is very important.
Do you really think that when people make a stand or protest about a moral act being wrong or right they are just expressing an opinion? Wouldnt that just undermine their protest and stand in the first place as an opinion means nothing about whether the act is truly right or wrong.