Problems in the argument:
Those such as yourself say that the universe is unintended.
Granted.
This includes every event that led to your existence.
A non sequitur and aslo clearly false. (Hint: How do we make babies ?)
This must also include every event that makes up your existence.
Not only false, but also begs the question.
I assume that the original argument means to restrict such a claim to the underlying physics and chemistry - which is still a question-begging example of the fallacy of composition.
Therefore every thought is the result of unintended causes and effects.
Since the premsies are false we have no need to accept this conclusion.
Objective truth exists.
A search for truth requires intent to find the truth.
Granted
If every action in the universe from the big bang to the final neuron firing in your search for truth is unintended and therefore random, then your search for truth is also random and therefore successful only by mere chance
As I understand this it also commits the same fallacy of composition noted above.
The question that really needs ot be addressed, is what is intent and where does it come from - and NOBODY has an answer that can be proven, rendering the whole thing an argument from ignorance.