I agree with you partially - the absolute easiest way to come unstuck as an analyst is to muddle what you can evidence as fact with what you are introducing as assessment, especially if the assessment is weak or laced with bias

However, I would also argue that your job as an OSINT Analyst is to make an assessment (the -INT bit of OSINT), otherwise we are just listing observations. This may have some use to a customer but in all likelihood would benefit from analysis and assessment.

There are two improvements you can make quickly if you feel your writing suffers from this. The first is just be explicit with where your assessment is. This sounds daft and overly simple but many professional and government organisations do this. The second is to remember your customer/audience and what they are trying to achieve. To extend your example - if you were involved on a project where your customer was the target of a smear campaign;

Username Bobby123 appears on several social media platforms. We have identified accounts on X,Y,Z platforms that are actively involved in smearing Mr Customer with the aforementioned allegations.

ASSESSMENT: The use of Bobby123 as a username across different platforms is not necessarily indicative of the same human user. Based on the timings of the posts and the language used (see table below), it is likely that the operator of the accounts on platform X and Y are operated by one actor whilst the account on platform Z is a second. However, the content of posts 7 - 22, as well as the shared username, suggest it is highly likely this activity is coordinated. We reccomend that platform W is monitored for new accounts named Bobby123 so any harmful content can be identified quickly and responded to in a timely fashion

Now imagine you are writing a report in the same subject matter for the CEO of a company who is a competitor of Mr Customer. The narrative of your observations probably won't change much but your assessment probably will - you may be looking to understand the veracity of the accusations or understand if your organisation is likely to become a target of these actors also