Can the other side just refuse my amendments?

They can, but far fewer refuse than people expect, and how you ask changes the answer. A vague complaint invites a no; handing over specific replacement wording invites a yes, because you have done the drafting for them. It also depends what point you are making. Some amendments simply correct terms drafted wrongly or that do not comply with the Construction Act, the law that sets minimum rights for most construction contracts, and those are hard to defend against. Conceding on the fixable points builds the credibility that wins the genuinely commercial asks about money and risk. And if a counterparty refuses every amendment on a heavily one sided draft, that itself tells you something about the relationship you are about to enter, so weigh it before you commit.

Say a demolition contractor sends back a marked up contract with six proposed changes rather than a list of grumbles. Two simply fix clauses that clash with the Construction Act, and the main contractor accepts those almost at once. Having conceded the easy points, the contractor has built enough goodwill that when they press the two changes they really care about, a shorter payment period and a cap on their liability, one is agreed outright and the other met halfway. The remaining two they let go. Presenting clean replacement wording and separating the fixable from the commercial turned what could have been a flat refusal into most of what they wanted.