"I think ... " means "My opinion is that ... " The user is speaking from their point of view, their experience.
This is not a universal statement.
( If you are not familiar with the technical category of 'universals' which comes from formal debate, it means, absolutes, general claims, based either on deductive analysis, or inductive reasoning based on extended evidence.)
A universal statement is signalled by such words as All/ Everyone/ Always/ Never. These should always contain deductive reasoning internal to the information givem, or evidence with sources cited.
The weakness of a universal is it can be refuted by a single contrary instamce.
Where the speaker states "In my opinion ..." or "I think .. " or similar, they are not making a true universal, even if other semiotic signals suggest it, because they have clearly provided a delimter which restricts the scope of their statement to their own perception.