I’ll just note that in Rabbi Rabinovitch’s view, nowadays when people do laundry in a washing machine, it is permitted to wash as usual. And that also makes sense: simply speaking, it seems from the Talmudic text that they prohibited labor that involves exertion, and today there is no exertion in doing laundry. Unless you understand that they made an independent decree specifically about laundering? If so, that’s a strange way to understand it…

To tell the truth, that is a very sensible argument. True, they did not prohibit laundering only because of exertion, but so that one would wash his clothes before the festival (like shaving). But it is reasonable that this was only because laundering used to be labor involving great effort (and then people tended to postpone it to the festival, and the problem of doing it during the festival was also greater).
But one still has to discuss the repeal of a decree once its reason has lapsed. Seemingly, we hold that decrees are not repealed when the reason lapses (and even the Raavad, who holds that they are, agrees that another formal court is needed to repeal them). However, here the prohibited act itself has changed, and this is not merely the lapse of the reason for the decree; rather, that old form of laundering no longer exists.
But in light of what I wrote at the beginning of my remarks—that the prohibition was not the exertion involved in laundering, but the concern that one would not wash before the holiday—it may be that this is not considered a case where the prohibited act itself has changed. What was prohibited is not really an act, but rather they required us to be concerned about a state of affairs (that one would wear unlaundered clothes). And if that is the definition, then the situation here is the ordinary lapse of the reason for the ordinance (not a change in the act itself), and there is room to be stringent.
Bottom line, I agree that there is definitely room to be lenient.

There is also room to be lenient for another reason: nowadays laundry is done almost every day, and therefore our normal situation is like that of someone who has only one garment.