Why don't pull and push bootstrap3 work?

Question

HTML

Why might not work? what did you do wrong?

<div class="b-rewiews__rewiew-name b-rewiews__rewiew-name--form row">
    <div class="col-sm-push-6 row">
        <div class="b-rewiews__group col-md-2 col-sm-6 col-xs-12"></div>
        <div class="b-rewiews__group col-md-2 col-sm-6 col-xs-12"></div>
    </div>
    <div class="col-sm-pull-6 row">
        <div class="b-rewiews__social-login col-md-2 col-sm-6 col-xs-12"></div>
        <div class="b-rewiews__rating-input b-rewiews__rating-input--no-autorized col-md-1 col-sm-6 col-xs-12"></div>
    </div>
</div>

Answer 1

For the parent element display: table; width: 100%
for internal
display: table-footer-group;
display: table-row-group;
display: table-header-group;

Answer 2

Because you use them together with row.
And in general, why do you use pushes / pools if you just need to write the col-sm-6 class:

<div class="b-rewiews__rewiew-name b-rewiews__rewiew-name--form row">
    <div class="col-sm-6">
        <div class="row">
            <div class="b-rewiews__group col-md-2 col-sm-6 col-xs-12"></div>
            <div class="b-rewiews__group col-md-2 col-sm-6 col-xs-12"></div>
        </div>
    </div>
    <div class="col-sm-6">
        <div class="row">
            <div class="b-rewiews__social-login col-md-2 col-sm-6 col-xs-12"></div>
            <div class="b-rewiews__rating-input b-rewiews__rating-input--no-autorized col-md-1 col-sm-6 col-xs-12"></div>
        </div>
    </div>
</div>