First of all, welcome.
Now, for me, the issue is proper punctuation and grammar go along way in helping to present a professional image to those outside of EMS who may stumble across our home on the web.
So many of us complain that we are not looked upon as professionals, yet some of those same people are either unable to use proper grammar and punctuation, or simply choose not to do so. When non-EMS people see this (and other) forums, it is the content of our posts that allow others to form an opinion about EMS personnel as a group. No matter how brilliant or insightful the ideas within a post may be, if the written words used to convey those ideas are poorly constructed it makes the entire group look bad.
It takes a relatively short amount of time for a behavior to become a habit. Constantly posting messages with poor English in them eventually makes that style of writing a habit which will spill over into PCRs and other paperwork required while working. This only detracts from the professional image most of us are working hard to try and convey.
Being professional is more than showing up in a neat, clean uniform or continuing to educate yourself. It also includes conveying thoughts and ideas in a well-organized, well-spoken manner. To do that, you must use proper English.
Keep in mind that the rest of the world will judge you by how you present yourself, and on the internet forums that is through the written word. It doesn't take any longer to use proper grammar within a sentence, or add the necessary punctuation.