I believe that assumption is misguided.
As a writer or blogger, you should take grammar seriously. Grammar is not a decorative feature of writing; it is crucial to it. Like the wheels on a car, Grammar moves your ideas along without friction.
Grammar gives a coherence to your statements, a coherence which is essential for your message to be properly understood and received.
Proper use of grammar gives your readers confidence in you. Poor grammar reflects poorly on you as a writer or even as a professional.
Grammar is never arbitrary, but reflects the agreed standards of a community. And as a writer using language, you exist within a community.
Yes, there are disputed points in grammar. There are areas which are debatable. Nevertheless, these are minor exceptions.
For instance, capitalizing personal names is an accepted rule. I would not refer to myself as ‘dayo adewoye’.
Using a period at the end of your sentence is standard.
There is a distinct difference between ‘There’ and ‘Their’.
Without a comma in the statement, ‘I like cooking my family and my pets’, we would think you are a psychopath.
In other words, grammar really matters.
Does this mean you are condemned to irrelevance if your knowledge of grammar isn’t A-grade? Of course not! Like every other skill, you can get better at it. Get books. Visit online platforms. Both the British Counciland Oxford Dictionaries have excellent resources to help you. All you need is the willingness and commitment.
Invest the time. Exert the effort. Work at it. It will pay off eventually.