First off, the image looks about as one might expect being taken at ISO 6400 - some visible noise. I have an older camera with about the same resolution and I would see that amount of noise at ISO 1600. However, the images usually print out very good at 8"x10". I find the solution is to just not look at the images zoomed in 1:1 on the screen unless actually in the process of manipulating the image. Joe noted this TIFF file was processed and exported in Lightroom using the Sony RAW file so that would make the original a full resolution image.
With the lens used it looks like it was shot at or close to wide open with a lens that still gives some depth of field - so a fair amount is still in acceptable focus, and of course the photographer wanted a high enough shutter speed (in this case 1/200th) to stop motion of the presenter; hence the high ISO.
It looks like there were lights for video. In this particular image the people in the audience are closer to those lights and are well lit up, while the presenter is of course receiving less light being farther away. A difficult lighting situation, and it looks like the photographer struck a balance.
I have supplied TIFF files to customers without doing anything to the images other than exporting to the TIFF format (where one can specify the image size) as the customer is then going to manipulate for use in their marketing materials. However, for most event photos I do some basic post processing - depending on the stated final use for the images - and supply those to the customer (this may be in images for initial review, then final in both small size for web and large size for print or the prints themselves).