"should" vs "should have to"

learnersdictionary.com:

(1a) All contestants should have to follow the same rules.

(2a) No one should have to tolerate that kind of treatment.

My variants without "have to":

(1b) All contestants should follow the same rules.

(2b) No one should tolerate that kind of treatment.

I don't know the difference between a- and b-variants in translating them into my language (Russian).

Could you explain to me what's the difference between them in English? Thanks!

1a means strictly

• All contestants should be required to follow the same rules,

  ie there should be one set of rules for all. This does not speak of the actual behaviour of contestants, but how the rules should be formulated and interpreted.

However, it's probably most often used to complain in retrospect about an incident involving apparent favouritism, equivalent to something like 'Why was Fanglio not disqualified for driving a car with 5 wheels when Starling Miss was?"

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1b means strictly that there is a requirement (possibly only a moral one, an expectation) on contestants that they ought to follow the same rules. Inviting, if there are lawbreakers,"You naughty contestants from Elbonia; you should have kept to the competition rules!" Or, modals being so polysemous, a statement that it is likely that all contestants actually will follow the same rules!

However, sentences such as 1b are certainly often used as deleted versions of 1a-type sentences in casual conversation. 'No one should be above the law.'

But I'd stick with the undeleted version in formal prose.

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2a speaks similarly about what the rules and implementation should be, but 2b is a definite call to arms, advising all who are thus abused to take action; here there is no other possible reading.