I am going to quick hit here.
I saw the episode and I thought I saw the Korean way of life unfold. You can also this in the Manny Pacquiao and BTS Jin episodes wherein Kim Jong Kook and Yang Se Chan are willing to forget about their age just to get chummy with the guests.
In this case, while Suk Jin thrives on his interaction with Yoo Jae Suk and the other cast members, it's not nice if they gang up on him.
Suk Jin as a character is annoying but he is way up there in terms of intelligence. Also, it's better to have either Jae Suk or Jong Kook tease him and perhaps have one of the younger members get their way from time to time.
With that said, I said OR on Jae Suk and Jong Kook. Not unless the two men are going to face a revolt with the rest of the members, ganging up on the eldest with everyone siding with them, despite all the wackiness is just bullying. This doesn't bid well with the Korean culture and it's not tolerated by other fans as well. Again, why would the others lower themselves when they have a high-profile guest and just rat on a dependable cast member?
Even if Suk Jin wanted this to happen, there is a reason why they have creative people behind the scenes. The female PD is new to her job and unlike the previous 1N2D PD, she started sluggishly in her job. With that said, this is the difference between Running Man and 1N2D. Bang Geul Yi came on board in the wake of Season 3's controversial end. Most Running Man members have maintained their good standing, apart from infractions here and there. Maybe this is a good way for Choi Hyung in to assert her dominance.
And as for comparing Lee Kwang Soo with Ji Suk Jin, it's not really comparable. First up, Kwang Soo is an actor first. Yes, he's a comedic character in variety shows and his dramas but there has been information that behind the scenes, Kwang Soo is deep - much like most actors dead serious with their craft. And then, prior to the new additions, Kwang Soo is the youngest cast member. In some ways, his antics and the Korean culture are enough reasons to justify (or defend) the cards dealt to him.
In some ways, Haha and Kang Gary had a similar dynamic before his departure. Yes, Gary has been called ugly but you can visibly see his displeasure when he was called "squid" by Haha. It's almost the same face Suk Jin had when he was called "dirty old geezer." Now, I am not insinuating anything but if you repeat a bad joke and it catches on, it is bound to piss a person off.
I think Suk Jin has been one of the biggest upsides of the current Running Man incarnation. Since they can't run all the time, they need his character to flourish in boring sit-down situations. Yes, there are times when he needs to tone down on the talking because he tends to hijack conversations (Yoo Jae Suk has this problem as well), but they also need to respect him.
This situation sucks because I like the current mafia atmosphere of Yoo Jae Suk and Kim Jong Kook. Yes, I root for the day when Jong Kook has had enough but at the moment, this situation is breaching the Jong Kook-Haha dynamic as well as the rest of Song Ji Hyo, Jeon So Min, and Yang Se Chan. Again, if they are setting up a turn between the two alphas or a revolt between the five remaining members, maybe the redemption arc would justify the backlash.
But if there's a public outcry, no amount of justification is enough because you have to give the audience what they want. And inasmuch as Running Man is big outside Korea, the show needs to think about what its national fans want. This is the reason why even if they want to rip nametags, they would rather do other things and I guess this is why they need to tone down on the whole Ji Suk Jin disrespect.