In my experience it's also annoying to be accused of slow play during this format..
I'm not one to let the clock run down but I know the type of players the OP means because I have come across them.. a little frustrating maybe but not that big of a deal in the grand scheme of things.. and my feeling was they were doing it in the hope I would forfeit.
I've been accused or told I'm slow twice now and both times it annoyed me. First time my opponent was constantly pulling once in a lifetime shots out of his backside and I was fighting hard just to try and stay in the game.. not to mention having several more shots... to then accuse someone of being slow when they had not once let the timer go close to expiring was poor form IMO.
The second time I handed a so called legend a bit of a lesson and he seemed to take exception to it... once again the shot clock never got close to expiring and a maximum of twice got inside 10 seconds remaining.. IMO he was no faster than me and took longer overall because he had more hits.
Keeping in mind I don't waste any time with tap-ins or simple putts and am just as keen as anyone to keep the game moving at a good pace.
A couple of things to consider... I play on mobile and it has a small screen.. to be precise it can take a bit of time to get the cursor where I want it.. but I always play to win and I'm gonna use the time i need to get the shot I'm trying to achieve and I recommend anyone with a competitive streak should do the same.
Using slow meter balls can also add a bit of time to each shot.. I also get bored waiting for the meter on the real slow balls.. but it's part of the game and out of my control if someone chooses to use those balls.
In summary and only with the mobile 45 second per shot format in mind... I think it's a bit petty to accuse someone of slow play when each player has the same 45 second time limit... it isn't very long and on some difficult shots the full time is needed to get it right.
A bit of a first world problem IMO... as some one else said there are a lot of variables in play and players should use their time wisely within reason... having said all that using the full 45 for a tap-in over and over would test anyone's patients.
On the other hand I've played against much lower players than me that seem to take forever.. but I am patient with them because they are learning the game and obviously want to be competitive.. it's never been a big deal. .generally when i have time to play WGT i'm not in that big of a hurry.