With the interest in third-party tools and bots surfacing on the forum, a common sentiment I found is "But how does that affect me?"
Well, it is pretty obvious that it can affect players who engage in PVP or market board PVP, as they are directly competing with bots and add-ons in a losing battle.
However, even for PVE content, third-party tools can affect players who do not use them negatively. I will give some examples from personal experience, as a PS5 player.
I was doing The Weapon's Refrain (Ultimate) (UWU) on Party Finder. There was a mechanic, Titan goals, that required 3 random players to line up quickly. The party finder standard was to have everyone install an add-on that calls out the order of line-up. For a party I was in, there were 2 PlayStation players and one player who claimed: "using third-party tools is against TOS". We were kicked out of the party.
Back when I was doing The Epic of Alexander (Ultimate) (TEA) when my static got to the last phase, "Perfect Alexander", the main mechanic was "Fate Calibration", which was not hard mechanics. Still, it took some practice as it was unique. After 2 wipes, my raid lead pressed everyone to use an add-on to solve the mechanics. Everyone except me decided to use it, I resisted by claiming it was not available on PS5. Luckily, I learned pretty quickly and only had those 2 wipes so that I did not wear others' patience thin.
I went back to PF for Dragonsong's Reprise (Ultimate) (DSR). When I got to the p6, the problem of people lying about their prog points was widespread, and it was common for the party to not see the claimed prog point at all. I tried to find a static, except the recruiters were asking for "prog logs", which I don't have. Then, when I got to the last phase, the lying about prog points became even more problematic, and some parties on PF started asking for "logs". Luckily, some people I have progged with in previous parties were able to provide their logs which have me in them, and I was able to clear.
I took a lot of extra effort to find a static for The Omega Protocol (Ultimate) (TOP) so that I could avoid similar issues. Fortunately, I was able to find one, and we cleared in a timely manner with moderate time investment. However, I would like to stress that it is not guaranteed for a static to prog an Ultimate without getting stuck at some point or to have member(s) unable/unwilling to continue to prog. It would be extra hard if one needs to find new member(s)/static mid-prog.
The above personal experience provides examples of how third-party tools can affect players who do not use them negatively even in PVE content, and how people who do not use them can be pressed into using them due to peer pressure.
When Yoshida wondered why would people use third-party tools during the TOP drama, I would argue that there exists an environment pressuring people to use them now, and it would be up to SE to change this environment.