25.0% is a bit understated. (ad blockers count, too). In June Chrome will be there as well.
Would keeping this code do any harm to my page loading process?
It is nearly impossible for anyone to answer this specific question without knowing what the code does exactly and where it appears on your page. The script is most likely blocking, that is nothing else on the page can happen until it is executed. What gets executed is impossible for me to know. The higher on the page it appears the greater the impact on the user. My guess, is that this script serves to flush some sort of queue ahead of loading it up with new ads and article to show on the current page. The duration of the impact of the blocking is likely minimal. You can use the "performance" tab in Chrome to see the exact impact.
The other question to ask is what impact will removing the code have on the functioning of Taboola, my guess is that it will break something. Just speculating, it will likely show old ads or articles that will not be relevant to the page. The issue with this is that it may not be obvious or easy to diagnose if is occurring.
Whether the script executes or not, anything that is on the page--as opposed to a separate .js file--will be loaded. Turning off scripts or using an ad blocker doesn't cause your browser to hold its breath, look away and refrain from downloading those extra bytes. Or kilobytes, depending on how verbose the code is. Why force users to expend bandwidth on something they're not going to use?
@Lucy24 you may be right. The assumption is that if you are including scripts for advertisements such as Taboola you would like those advertisements to show correctly. It seems a little non-sensical to call a portion of the ad code and then not call the rest in order to speed up your page. Ditch it all or show it all.
One client, this goes back a few years, wondered why his pages were loading so slowly. Took about 18 seconds to figure it out after looking at the source code: Inline css created by dumping MS Word docs as html, cut paste, and doing it over and over and over.... Whew! Talk about useless code!