All knowledge is biased (?)

From last class, we saw that there were two types of knowledge. The first one is Knowledge by Acquaintance, which is a sort of knowledge we know by experiencing something (i.e. by being "acquainted" with it). With the given example "I Know Paris", we saw how the definition of knowledge varied depending on who you are, a tourist or a local resident for a period of time. For a tourist it could mean the monuments, the roads or even the culture. However, for the local resident, it could imply the Parisian life, what Paris means to that person, or experiences which the person may have had in/around Paris. It could also mean the personal attachment the person shares with the city. This sort of knowledge is something that is felt, perceived, and in a sense, it can be termed as "private knowledge" as rarely would you expect many people to know what you know about a city (by "know" here, I mean your experiences or your attachment).
The second one is Knowledge by Description, the sort of knowledge which we obtain from a secondary source, and not by personally experiencing a thing. The given example stated that "I Know Paris is the capital of France.", and people said they knew that Paris was the capital of France in various ways:

1. Somebody told them
2. From an atlas/newspaper/magazine (written source)
3. School/internet
4. Live(d) in Paris

This is the sort of knowledge that is published and printed in various places and which people are sure "exists". This can be termed as "public knowledge" as it is taken to be a fact, something that is "universally accepted".
Also, it was seen that all opinion is knowledge, as having an opinion means that you know such an opinion exists. That gave rise to the concept of "biased knowledge" and about how much we know is actually true and how much is biased. According to me, all knowledge is biased, and all knowledge is based COMPLETELY on opinion and what people perceive to be true. It is what people find best-fitting to the current understanding of the current aspects which they know about. Every "fact" and piece of "knowledge" is based on the most concurrent opinion between the people deciding on that fact. What seems to fit current understanding may be far from the actual truth, but is still taken to be "knowledge" as it seems to fit understanding. As a result, in my opinion, all opinion is based on more opinion, and all knowledge is biased.