I can't say for sure, but I suspect it was a reaction to ALGOL-68. Creators of later Algolish languages usually made a point of rejecting features of Algol-68 they saw as prone to abuse.

And the block expressions in Algol-68 were certainly used and abused. Basically, the type and value of a block (BEGIN ... END or ( ... )) are those of its last expression, so you can put them anywhere. For example, Algol-68 has the looping construct WHILE <condition> DO <body> OD, but not C's `do <body> while (<condition>)`. So what do you do if you want to have the test at the end of the loop body? Simply

    WHILE (
       <body>;
       <condition>
       )
    DO SKIP OD

I guess you'd get used to those idioms eventually, or some coding conventions would have arisen if the language had been successful. But I can understand language creators looking at that and seeing how getting rid of it simplifies not only their compilers but also the programs written in their languages.