Hajj is one of the 5 pillars of the faith, it can't be "boycotted" just because a bunch of sycophantic a-holes are running the country. The first pilgrimage was performed when Makkah was under the control of tyrants after a treaty between Muhammad and the Quraysh tribe (controlling Makkah) was made.

No Muslim worth their salt would boycott Hajj. The reasons you give are farcical and aimed to guilt-trip people, the one where people are too old or physically unable are not cases of boycotting, they're genuine exceptions to the obligation. Hajj has occurred since long before the House of Saud existed and will continue to occur long after the House of Saud falls.

Of all the things you mentioned to do to "help", you didn't say Americans should tell their government to stop aiding the Saudis in everything they do. The US sells Saudi Arabia all the weaponry it has, it takes Saudis side against Iran (sanctioning the latter), it strongly benefits from Saudi sale of oil (petrodollar). It's nigh impossible to boycott a state that makes most of its revenue from a required commodity. Hajj isn't keeping the HoS running, the US+co. and the petrodollar is.

The verse you quote means do not worship idols (statues etc.) and that there must be no idols inside the Ka'aba/Masjid al-Haram (of which there once were - they were removed/destroyed).

I agree with you that the HoS is despicable, but not that Hajj can be boycotted or that it's "delegitimised" in any way.